first time travel in history

Where Does the Concept of Time Travel Come From?

Time; he's waiting in the wings.

Wormholes have been proposed as one possible means of traveling through time.

The dream of traveling through time is both ancient and universal. But where did humanity's fascination with time travel begin, and why is the idea so appealing?

The concept of time travel — moving through time the way we move through three-dimensional space — may in fact be hardwired into our perception of time . Linguists have recognized that we are essentially incapable of talking about temporal matters without referencing spatial ones. "In language — any language — no two domains are more intimately linked than space and time," wrote Israeli linguist Guy Deutscher in his 2005 book "The Unfolding of Language." "Even if we are not always aware of it, we invariably speak of time in terms of space, and this reflects the fact that we think of time in terms of space."

Deutscher reminds us that when we plan to meet a friend "around" lunchtime, we are using a metaphor, since lunchtime doesn't have any physical sides. He similarly points out that time can not literally be "long" or "short" like a stick, nor "pass" like a train, or even go "forward" or "backward" any more than it goes sideways, diagonal or down.

Related: Why Does Time Fly When You're Having Fun?

Perhaps because of this connection between space and time, the possibility that time can be experienced in different ways and traveled through has surprisingly early roots. One of the first known examples of time travel appears in the Mahabharata, an ancient Sanskrit epic poem compiled around 400 B.C., Lisa Yaszek, a professor of science fiction studies at the Georgia Institute of Technology in Atlanta, told Live Science

In the Mahabharata is a story about King Kakudmi, who lived millions of years ago and sought a suitable husband for his beautiful and accomplished daughter, Revati. The two travel to the home of the creator god Brahma to ask for advice. But while in Brahma's plane of existence, they must wait as the god listens to a 20-minute song, after which Brahma explains that time moves differently in the heavens than on Earth. It turned out that "27 chatur-yugas" had passed, or more than 116 million years, according to an online summary , and so everyone Kakudmi and Revati had ever known, including family members and potential suitors, was dead. After this shock, the story closes on a somewhat happy ending in that Revati is betrothed to Balarama, twin brother of the deity Krishna.

Time is fleeting

To Yaszek, the tale provides an example of what we now call time dilation , in which different observers measure different lengths of time based on their relative frames of reference, a part of Einstein's theory of relativity.

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Such time-slip stories are widespread throughout the world, Yaszek said, citing a Middle Eastern tale from the first century BCE about a Jewish miracle worker who sleeps beneath a newly-planted carob tree and wakes up 70 years later to find it has now matured and borne fruit (carob trees are notorious for how long they take to produce their first harvest). Another instance can be found in an eighth-century Japanese fable about a fisherman named Urashima Tarō who travels to an undersea palace and falls in love with a princess. Tarō finds that, when he returns home, 100 years have passed, according to a translation of the tale published online by the University of South Florida .

In the early-modern era of the 1700 and 1800s, the sleep-story version of time travel grew more popular, Yaszek said. Examples include the classic tale of Rip Van Winkle, as well as books like Edward Belamy's utopian 1888 novel "Looking Backwards," in which a man wakes up in the year 2000, and the H.G. Wells 1899 novel "The Sleeper Awakes," about a man who slumbers for centuries and wakes to a completely transformed London.

Related: Science Fiction or Fact: Is Time Travel Possible ?

In other stories from this period, people also start to be able to move backward in time. In Mark Twain’s 1889 satire "A Connecticut Yankee in King Arthur's Court," a blow to the head propels an engineer back to the reign of the legendary British monarch. Objects that can send someone through time begin to appear as well, mainly clocks, such as in Edward Page Mitchell's 1881 story "The Clock that Went Backwards" or Lewis Carrol's 1889 children's fantasy "Sylvie and Bruno," where the characters possess a watch that is a type of time machine .

The explosion of such stories during this era might come from the fact that people were "beginning to standardize time, and orient themselves to clocks more frequently," Yaszek said.

Time after time

Wells provided one of the most enduring time-travel plots in his 1895 novella "The Time Machine," which included the innovation of a craft that can move forward and backward through long spans of time. "This is when we’re getting steam engines and trains and the first automobiles," Yaszek said. "I think it’s no surprise that Wells suddenly thinks: 'Hey, maybe we can use a vehicle to travel through time.'"

Because it is such a rich visual icon, many beloved time-travel stories written after this have included a striking time machine, Yaszek said, referencing The Doctor's blue police box — the TARDIS — in the long-running BBC series "Doctor Who," and "Back to the Future"'s silver luxury speedster, the DeLorean .

More recently, time travel has been used to examine our relationship with the past, Yaszek said, in particular in pieces written by women and people of color. Octavia Butler's 1979 novel "Kindred" about a modern woman who visits her pre-Civil-War ancestors is "a marvelous story that really asks us to rethink black and white relations through history," she said. And a contemporary web series called " Send Me " involves an African-American psychic who can guide people back to antebellum times and witness slavery.

"I'm really excited about stories like that," Yaszek said. "They help us re-see history from new perspectives."

Time travel has found a home in a wide variety of genres and media, including comedies such as "Groundhog Day" and "Bill and Ted's Excellent Adventure" as well as video games like Nintendo's "The Legend of Zelda: Majora's Mask" and the indie game "Braid."

Yaszek suggested that this malleability and ubiquity speaks to time travel tales' ability to offer an escape from our normal reality. "They let us imagine that we can break free from the grip of linear time," she said. "And somehow get a new perspective on the human experience, either our own or humanity as a whole, and I think that feels so exciting to us."

That modern people are often drawn to time-machine stories in particular might reflect the fact that we live in a technological world, she added. Yet time travel's appeal certainly has deeper roots, interwoven into the very fabric of our language and appearing in some of our earliest imaginings.

"I think it's a way to make sense of the otherwise intangible and inexplicable, because it's hard to grasp time," Yaszek said. "But this is one of the final frontiers, the frontier of time, of life and death. And we're all moving forward, we're all traveling through time."

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Originally published on Live Science .

Adam Mann is a freelance journalist with over a decade of experience, specializing in astronomy and physics stories. He has a bachelor's degree in astrophysics from UC Berkeley. His work has appeared in the New Yorker, New York Times, National Geographic, Wall Street Journal, Wired, Nature, Science, and many other places. He lives in Oakland, California, where he enjoys riding his bike.

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For most of human history, the world didn’t change very quickly. Until the 1700s, kids could largely expect their lives to be similar to their parents, and that their children would have an experience very similar to their own, too. There were obviously changes in how humans lived over longer stretches of time, but nothing that even different generations could easily observe.

My first introduction to science fiction was Valérian and Laureline. I was ten years old. Every Wednesday there was a magazine called Pilote in France, and there was two pages of Valerian every week. It was the first time I’d seen a girl and a guy in space, agents travelling in time and space. That was amazing.

The past is written. The present? We have to deal with it. But the future is a white page. So I don’t understand why people on this white page are putting all this darkness.

God! Let’s have some color! Let’s have some fun! Let’s at least imagine a better world. Maybe we won’t be able to do it, but we have to try.

The industrial revolution changed all of this. For the first time in human history, the pace of technological change was visible within a human lifespan.

It is not a coincidence that it was only after science and technological change became a normal part of the human experience, that time travel became something we dreamed of.

Time travel is actually somewhat unique in science fiction. Many core concepts have their origins earlier in history.

The historical roots of the concept of a 'robot' can be seen in Jewish folklore for example: Golems were anthropomorphic beings sculpted from clay. In Greek mythology, characters would travel to other worlds, and it's no coincidence that The Matrix features a character called Persephone. But time travel is different.

The first real work to envisage travelling in time was The Time Machine by HG Wells, which was published in 1895.

The book tells the story of a scientist who builds a machine that will take him to the year 802,701 - a world in which ape-like Morlocks are evolutionary descendants of humanity, and have regressed to a primitive lifestyle.

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The book was a product of its time - both in terms of the science played upon (Charles Darwin had only published Origin of the Species 35 years earlier), and the racist attitudes: it is speculated that the Morlocks were inspired by the Morlachs, a real ethnic group in the Balkans who were often characterised as “primitive”.

Real science

But of course, this was science fiction - what about science fact? The two have always been closely linked, and during the early days it was no different. In 1907, the physicist Hermann Minkowski first argued that Einstein’s Special Relativity could be expressed in geometric terms as a fourth dimension (to add to our known three) - which is exactly how Wells visualised time travel in his work of fiction.

The development of Special and then General Relativity was significant as it provided the theoretical backbone for how time travel could be conceived in scientific terms. In 1949 Kurt Gödel took Einstein’s work and came up with a solution which as a mathematical necessity included what he called “closed timelike curves” - the idea that if you travel far enough, time will loop back around (like how if you keep flying East, you’ll eventually end up back where you started).

Minkowski's expression of the fourth dimension, no special glasses needed

In other words, using what became known as the Gödel Metric, it is theoretically possible to travel between any one point in time and space and any other.

There was just one problem: for Gödel’s theory to be right, the universe would have to be spinning - and scientists don’t believe that it is. So while the maths might make sense, Gödel’s universe does not appear to be the one we’re actually living in. Though he never gave up hope that he might be right: Apparently even on this deathbed, he would ask if anyone has found evidence of a spinning universe. And if he does ever turn out to be right, it means that time travel can happen, and is actually fairly straightforward (well, as far as physics goes anyway).

Since Gödel, scientists have continued to hypothesise about time travel, with perhaps the best known example being tachyons - or particles that move faster than the speed of light (therefore, effectively travelling in time). So far, despite one false alarm at CERN in 2011, there is no evidence that they actually exist.

Chancers and hoaxes

Of course, the lack of real science when it comes to time travel has not stopped some people from claiming to have done it. With the likes of Marty McFly and Doctor Who on the brain, chancers and hoaxers have realised that time travel is immediately a compelling prospect. Here’s a couple of amusing examples.

At the turn of the millennium, when the internet was still in its infancy, forums were captivated by the story of John Titor. Titor claimed he was from the year 2036, and had been sent back in time by the government to obtain an IBM 5100 computer. The thinking appeared to be that by obtaining the computer, the government could find a solution to the UNIX 2038 bug - in which clocks could be reset, Millennium Bug-style, leading to chaos everywhere.

Posting on the 'Time Travel Institute' forums, Titor went into details on how his time machine worked: It was powered by “two top-spin, dual positive singularities”, and used an X-ray venting system. He also gave a potted history of what humanity could expect: A new American civil war in 2004, and World War III in 2015. He also claimed the “many worlds” interpretation of quantum physics was true, hence why he wasn’t violating the so-called “grandfather paradox”.

Titor claimed he was from the year 2036, and had been sent back in time by the government to obtain an IBM 5100 computer.

Okay, so he probably wasn’t a real time traveller, but in the early days of the internet, when anonymity was more commonplace, he truly captured the imaginations of nerdy early adopters who perhaps, just a little bit, hoped that he might be the real thing.

More recently, in 2013, an Iranian scientist named Ali Razeghi claimed to have invented a time machine of sorts. It was supposedly capable of predicting the next 5-8 years for an individual, with up to 98% accuracy. According to The Telegraph , Razeghi said the invention fits into the size of a standard PC case and “It will not take you into the future, it will bring the future to you”. The idea is that the Iranian government could use it to predict future security threats and military confrontations. So perhaps it is time to check in and see if he managed to predict Donald Trump?

The actual Time Lord, Professor Stephen Hawking

So is this the best we can do? Will we ever manage to crack time travel? Some scientists are still sceptical that it could ever be possible. This includes Stephen Hawking, who proposed the 'Chronology Protection Conjecture' – which is what it sounds like. Essentially, he argues that the laws of physics are as they are to specifically make time travel impossible – on all but “submicroscopic” scales. Essentially, this is to protect how causality works, as if we are suddenly allowed to travel back and kill our grandfathers, it would create massive time paradoxes.

Hawking revealed to Ars Technica in 2012 how he had held a party for time travellers, but only sent out invitations after the date it was held. So did the party support his argument that time travel is impossible? Or did he end up spending the evening in the company of John Titor and Doctor Who?

“I sat there a long time, but no one came”, he said, much to our disappointment.

Huge thanks to Stephen Jorgenson-Murray for walking us through some of the more brain-mangling science for this article.

To celebrate the release of Valerian and the City of a Thousand Planets , Luc Besson is today behind the lens at TechRadar. Here’s what we’ve got in store for you:

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A brief history of time travel

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Of all time travel's paradoxes, here's the strangest of them all: hop on a TARDIS back to 1894 and the concept didn't even exist. "Time travel is a new idea," explains New York-based author James Gleick, 62. "It's a very modern myth." Gleick's entertaining Time Travel: A History , out in hardback in February, quantum leaps from HG Wells's The Time Machine - the original - via Proust and alt-history right up to your Twitter timeline. Until we get the DeLorean working for real, fellow travellers, consider it the next best thing.

The Mahabharata

Time travel appears in Hindu text The Mahabharata, and in stories such as Washington Irving's Rip Van Winkle (1819) - but it usually only involved a one-way trip. "People fell asleep, and woke  up in the future," says Gleick.

HG Wells's The Time Machine

"The idea of time travel with volition, in either direction, didn't arrive until Wells," says Gleick. It explains that time is a dimension - something not widely accepted until Einstein's theories in 1905.

Henri Bergson's Time And Free Will

Bergson's thesis is published soon after Wells's novel. "Bergson is a friend of Marcel Proust," says Gleick. Soon Proust et al are jumping on the idea of time travel to explore free will - and influencing new sci-fi in return.

Time Capsules

The idea of preserving a time stamp only arose in the 1930s in Scientific American. "It's the most pedestrian form of time travel: sending something into the future at a rate of one minute per minute."

Robert A Heinlein's By His Bootstraps

Heinlein's short story, published in Astounding Science Fiction, introduces the idea of a character appearing in multiple timelines, meeting themselves amid complex - and funny - paradoxes.

William Gibson's The Peripheral

Gleick cites Gibson's unique twist on the genre: "We can't send people, but what if you could send information back to the past?" It's a chilling new take. "It shows how our cultural conception of time is changing."

This article was originally published by WIRED UK

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Time Travel

There is an extensive literature on time travel in both philosophy and physics. Part of the great interest of the topic stems from the fact that reasons have been given both for thinking that time travel is physically possible—and for thinking that it is logically impossible! This entry deals primarily with philosophical issues; issues related to the physics of time travel are covered in the separate entries on time travel and modern physics and time machines . We begin with the definitional question: what is time travel? We then turn to the major objection to the possibility of backwards time travel: the Grandfather paradox. Next, issues concerning causation are discussed—and then, issues in the metaphysics of time and change. We end with a discussion of the question why, if backwards time travel will ever occur, we have not been visited by time travellers from the future.

1.1 Time Discrepancy

1.2 changing the past, 2.1 can and cannot, 2.2 improbable coincidences, 2.3 inexplicable occurrences, 3.1 backwards causation, 3.2 causal loops, 4.1 time travel and time, 4.2 time travel and change, 5. where are the time travellers, other internet resources, related entries, 1. what is time travel.

There is a number of rather different scenarios which would seem, intuitively, to count as ‘time travel’—and a number of scenarios which, while sharing certain features with some of the time travel cases, seem nevertheless not to count as genuine time travel: [ 1 ]

Time travel Doctor . Doctor Who steps into a machine in 2024. Observers outside the machine see it disappear. Inside the machine, time seems to Doctor Who to pass for ten minutes. Observers in 1984 (or 3072) see the machine appear out of nowhere. Doctor Who steps out. [ 2 ] Leap . The time traveller takes hold of a special device (or steps into a machine) and suddenly disappears; she appears at an earlier (or later) time. Unlike in Doctor , the time traveller experiences no lapse of time between her departure and arrival: from her point of view, she instantaneously appears at the destination time. [ 3 ] Putnam . Oscar Smith steps into a machine in 2024. From his point of view, things proceed much as in Doctor : time seems to Oscar Smith to pass for a while; then he steps out in 1984. For observers outside the machine, things proceed differently. Observers of Oscar’s arrival in the past see a time machine suddenly appear out of nowhere and immediately divide into two copies of itself: Oscar Smith steps out of one; and (through the window) they see inside the other something that looks just like what they would see if a film of Oscar Smith were played backwards (his hair gets shorter; food comes out of his mouth and goes back into his lunch box in a pristine, uneaten state; etc.). Observers of Oscar’s departure from the future do not simply see his time machine disappear after he gets into it: they see it collide with the apparently backwards-running machine just described, in such a way that both are simultaneously annihilated. [ 4 ] Gödel . The time traveller steps into an ordinary rocket ship (not a special time machine) and flies off on a certain course. At no point does she disappear (as in Leap ) or ‘turn back in time’ (as in Putnam )—yet thanks to the overall structure of spacetime (as conceived in the General Theory of Relativity), the traveller arrives at a point in the past (or future) of her departure. (Compare the way in which someone can travel continuously westwards, and arrive to the east of her departure point, thanks to the overall curved structure of the surface of the earth.) [ 5 ] Einstein . The time traveller steps into an ordinary rocket ship and flies off at high speed on a round trip. When he returns to Earth, thanks to certain effects predicted by the Special Theory of Relativity, only a very small amount of time has elapsed for him—he has aged only a few months—while a great deal of time has passed on Earth: it is now hundreds of years in the future of his time of departure. [ 6 ] Not time travel Sleep . One is very tired, and falls into a deep sleep. When one awakes twelve hours later, it seems from one’s own point of view that hardly any time has passed. Coma . One is in a coma for a number of years and then awakes, at which point it seems from one’s own point of view that hardly any time has passed. Cryogenics . One is cryogenically frozen for hundreds of years. Upon being woken, it seems from one’s own point of view that hardly any time has passed. Virtual . One enters a highly realistic, interactive virtual reality simulator in which some past era has been recreated down to the finest detail. Crystal . One looks into a crystal ball and sees what happened at some past time, or will happen at some future time. (Imagine that the crystal ball really works—like a closed-circuit security monitor, except that the vision genuinely comes from some past or future time. Even so, the person looking at the crystal ball is not thereby a time traveller.) Waiting . One enters one’s closet and stays there for seven hours. When one emerges, one has ‘arrived’ seven hours in the future of one’s ‘departure’. Dateline . One departs at 8pm on Monday, flies for fourteen hours, and arrives at 10pm on Monday.

A satisfactory definition of time travel would, at least, need to classify the cases in the right way. There might be some surprises—perhaps, on the best definition of ‘time travel’, Cryogenics turns out to be time travel after all—but it should certainly be the case, for example, that Gödel counts as time travel and that Sleep and Waiting do not. [ 7 ]

In fact there is no entirely satisfactory definition of ‘time travel’ in the literature. The most popular definition is the one given by Lewis (1976, 145–6):

What is time travel? Inevitably, it involves a discrepancy between time and time. Any traveller departs and then arrives at his destination; the time elapsed from departure to arrival…is the duration of the journey. But if he is a time traveller, the separation in time between departure and arrival does not equal the duration of his journey.…How can it be that the same two events, his departure and his arrival, are separated by two unequal amounts of time?…I reply by distinguishing time itself, external time as I shall also call it, from the personal time of a particular time traveller: roughly, that which is measured by his wristwatch. His journey takes an hour of his personal time, let us say…But the arrival is more than an hour after the departure in external time, if he travels toward the future; or the arrival is before the departure in external time…if he travels toward the past.

This correctly excludes Waiting —where the length of the ‘journey’ precisely matches the separation between ‘arrival’ and ‘departure’—and Crystal , where there is no journey at all—and it includes Doctor . It has trouble with Gödel , however—because when the overall structure of spacetime is as twisted as it is in the sort of case Gödel imagined, the notion of external time (“time itself”) loses its grip.

Another definition of time travel that one sometimes encounters in the literature (Arntzenius, 2006, 602) (Smeenk and Wüthrich, 2011, 5, 26) equates time travel with the existence of CTC’s: closed timelike curves. A curve in this context is a line in spacetime; it is timelike if it could represent the career of a material object; and it is closed if it returns to its starting point (i.e. in spacetime—not merely in space). This now includes Gödel —but it excludes Einstein .

The lack of an adequate definition of ‘time travel’ does not matter for our purposes here. [ 8 ] It suffices that we have clear cases of (what would count as) time travel—and that these cases give rise to all the problems that we shall wish to discuss.

Some authors (in philosophy, physics and science fiction) consider ‘time travel’ scenarios in which there are two temporal dimensions (e.g. Meiland (1974)), and others consider scenarios in which there are multiple ‘parallel’ universes—each one with its own four-dimensional spacetime (e.g. Deutsch and Lockwood (1994)). There is a question whether travelling to another version of 2001 (i.e. not the very same version one experienced in the past)—a version at a different point on the second time dimension, or in a different parallel universe—is really time travel, or whether it is more akin to Virtual . In any case, this kind of scenario does not give rise to many of the problems thrown up by the idea of travelling to the very same past one experienced in one’s younger days. It is these problems that form the primary focus of the present entry, and so we shall not have much to say about other kinds of ‘time travel’ scenario in what follows.

One objection to the possibility of time travel flows directly from attempts to define it in anything like Lewis’s way. The worry is that because time travel involves “a discrepancy between time and time”, time travel scenarios are simply incoherent. The time traveller traverses thirty years in one year; she is 51 years old 21 years after her birth; she dies at the age of 100, 200 years before her birth; and so on. The objection is that these are straightforward contradictions: the basic description of what time travel involves is inconsistent; therefore time travel is logically impossible. [ 9 ]

There must be something wrong with this objection, because it would show Einstein to be logically impossible—whereas this sort of future-directed time travel has actually been observed (albeit on a much smaller scale—but that does not affect the present point) (Hafele and Keating, 1972b,a). The most common response to the objection is that there is no contradiction because the interval of time traversed by the time traveller and the duration of her journey are measured with respect to different frames of reference: there is thus no reason why they should coincide. A similar point applies to the discrepancy between the time elapsed since the time traveller’s birth and her age upon arrival. There is no more of a contradiction here than in the fact that Melbourne is both 800 kilometres away from Sydney—along the main highway—and 1200 kilometres away—along the coast road. [ 10 ]

Before leaving the question ‘What is time travel?’ we should note the crucial distinction between changing the past and participating in (aka affecting or influencing) the past. [ 11 ] In the popular imagination, backwards time travel would allow one to change the past: to right the wrongs of history, to prevent one’s younger self doing things one later regretted, and so on. In a model with a single past, however, this idea is incoherent: the very description of the case involves a contradiction (e.g. the time traveller burns all her diaries at midnight on her fortieth birthday in 1976, and does not burn all her diaries at midnight on her fortieth birthday in 1976). It is not as if there are two versions of the past: the original one, without the time traveller present, and then a second version, with the time traveller playing a role. There is just one past—and two perspectives on it: the perspective of the younger self, and the perspective of the older time travelling self. If these perspectives are inconsistent (e.g. an event occurs in one but not the other) then the time travel scenario is incoherent.

This means that time travellers can do less than we might have hoped: they cannot right the wrongs of history; they cannot even stir a speck of dust on a certain day in the past if, on that day, the speck was in fact unmoved. But this does not mean that time travellers must be entirely powerless in the past: while they cannot do anything that did not actually happen, they can (in principle) do anything that did happen. Time travellers cannot change the past: they cannot make it different from the way it was—but they can participate in it: they can be amongst the people who did make the past the way it was. [ 12 ]

What about models involving two temporal dimensions, or parallel universes—do they allow for coherent scenarios in which the past is changed? [ 13 ] There is certainly no contradiction in saying that the time traveller burns all her diaries at midnight on her fortieth birthday in 1976 in universe 1 (or at hypertime A ), and does not burn all her diaries at midnight on her fortieth birthday in 1976 in universe 2 (or at hypertime B ). The question is whether this kind of story involves changing the past in the sense originally envisaged: righting the wrongs of history, preventing subsequently regretted actions, and so on. Goddu (2003) and van Inwagen (2010) argue that it does (in the context of particular hypertime models), while Smith (1997, 365–6; 2015) argues that it does not: that it involves avoiding the past—leaving it untouched while travelling to a different version of the past in which things proceed differently.

2. The Grandfather Paradox

The most important objection to the logical possibility of backwards time travel is the so-called Grandfather paradox. This paradox has actually convinced many people that backwards time travel is impossible:

The dead giveaway that true time-travel is flatly impossible arises from the well-known “paradoxes” it entails. The classic example is “What if you go back into the past and kill your grandfather when he was still a little boy?”…So complex and hopeless are the paradoxes…that the easiest way out of the irrational chaos that results is to suppose that true time-travel is, and forever will be, impossible. (Asimov 1995 [2003, 276–7]) travel into one’s past…would seem to give rise to all sorts of logical problems, if you were able to change history. For example, what would happen if you killed your parents before you were born. It might be that one could avoid such paradoxes by some modification of the concept of free will. But this will not be necessary if what I call the chronology protection conjecture is correct: The laws of physics prevent closed timelike curves from appearing . (Hawking, 1992, 604) [ 14 ]

The paradox comes in different forms. Here’s one version:

If time travel was logically possible then the time traveller could return to the past and in a suicidal rage destroy his time machine before it was completed and murder his younger self. But if this was so a necessary condition for the time trip to have occurred at all is removed, and we should then conclude that the time trip did not occur. Hence if the time trip did occur, then it did not occur. Hence it did not occur, and it is necessary that it did not occur. To reply, as it is standardly done, that our time traveller cannot change the past in this way, is a petitio principii . Why is it that the time traveller is constrained in this way? What mysterious force stills his sudden suicidal rage? (Smith, 1985, 58)

The idea is that backwards time travel is impossible because if it occurred, time travellers would attempt to do things such as kill their younger selves (or their grandfathers etc.). We know that doing these things—indeed, changing the past in any way—is impossible. But were there time travel, there would then be nothing left to stop these things happening. If we let things get to the stage where the time traveller is facing Grandfather with a loaded weapon, then there is nothing left to prevent the impossible from occurring. So we must draw the line earlier: it must be impossible for someone to get into this situation at all; that is, backwards time travel must be impossible.

In order to defend the possibility of time travel in the face of this argument we need to show that time travel is not a sure route to doing the impossible. So, given that a time traveller has gone to the past and is facing Grandfather, what could stop her killing Grandfather? Some science fiction authors resort to the idea of chaperones or time guardians who prevent time travellers from changing the past—or to mysterious forces of logic. But it is hard to take these ideas seriously—and more importantly, it is hard to make them work in detail when we remember that changing the past is impossible. (The chaperone is acting to ensure that the past remains as it was—but the only reason it ever was that way is because of his very actions.) [ 15 ] Fortunately there is a better response—also to be found in the science fiction literature, and brought to the attention of philosophers by Lewis (1976). What would stop the time traveller doing the impossible? She would fail “for some commonplace reason”, as Lewis (1976, 150) puts it. Her gun might jam, a noise might distract her, she might slip on a banana peel, etc. Nothing more than such ordinary occurrences is required to stop the time traveller killing Grandfather. Hence backwards time travel does not entail the occurrence of impossible events—and so the above objection is defused.

A problem remains. Suppose Tim, a time-traveller, is facing his grandfather with a loaded gun. Can Tim kill Grandfather? On the one hand, yes he can. He is an excellent shot; there is no chaperone to stop him; the laws of logic will not magically stay his hand; he hates Grandfather and will not hesitate to pull the trigger; etc. On the other hand, no he can’t. To kill Grandfather would be to change the past, and no-one can do that (not to mention the fact that if Grandfather died, then Tim would not have been born). So we have a contradiction: Tim can kill Grandfather and Tim cannot kill Grandfather. Time travel thus leads to a contradiction: so it is impossible.

Note the difference between this version of the Grandfather paradox and the version considered above. In the earlier version, the contradiction happens if Tim kills Grandfather. The solution was to say that Tim can go into the past without killing Grandfather—hence time travel does not entail a contradiction. In the new version, the contradiction happens as soon as Tim gets to the past. Of course Tim does not kill Grandfather—but we still have a contradiction anyway: for he both can do it, and cannot do it. As Lewis puts it:

Could a time traveler change the past? It seems not: the events of a past moment could no more change than numbers could. Yet it seems that he would be as able as anyone to do things that would change the past if he did them. If a time traveler visiting the past both could and couldn’t do something that would change it, then there cannot possibly be such a time traveler. (Lewis, 1976, 149)

Lewis’s own solution to this problem has been widely accepted. [ 16 ] It turns on the idea that to say that something can happen is to say that its occurrence is compossible with certain facts, where context determines (more or less) which facts are the relevant ones. Tim’s killing Grandfather in 1921 is compossible with the facts about his weapon, training, state of mind, and so on. It is not compossible with further facts, such as the fact that Grandfather did not die in 1921. Thus ‘Tim can kill Grandfather’ is true in one sense (relative to one set of facts) and false in another sense (relative to another set of facts)—but there is no single sense in which it is both true and false. So there is no contradiction here—merely an equivocation.

Another response is that of Vihvelin (1996), who argues that there is no contradiction here because ‘Tim can kill Grandfather’ is simply false (i.e. contra Lewis, there is no legitimate sense in which it is true). According to Vihvelin, for ‘Tim can kill Grandfather’ to be true, there must be at least some occasions on which ‘If Tim had tried to kill Grandfather, he would or at least might have succeeded’ is true—but, Vihvelin argues, at any world remotely like ours, the latter counterfactual is always false. [ 17 ]

Return to the original version of the Grandfather paradox and Lewis’s ‘commonplace reasons’ response to it. This response engenders a new objection—due to Horwich (1987)—not to the possibility but to the probability of backwards time travel.

Think about correlated events in general. Whenever we see two things frequently occurring together, this is because one of them causes the other, or some third thing causes both. Horwich calls this the Principle of V-Correlation:

if events of type A and B are associated with one another, then either there is always a chain of events between them…or else we find an earlier event of type C that links up with A and B by two such chains of events. What we do not see is…an inverse fork—in which A and B are connected only with a characteristic subsequent event, but no preceding one. (Horwich, 1987, 97–8)

For example, suppose that two students turn up to class wearing the same outfits. That could just be a coincidence (i.e. there is no common cause, and no direct causal link between the two events). If it happens every week for the whole semester, it is possible that it is a coincidence, but this is extremely unlikely . Normally, we see this sort of extensive correlation only if either there is a common cause (e.g. both students have product endorsement deals with the same clothing company, or both slavishly copy the same influencer) or a direct causal link (e.g. one student is copying the other).

Now consider the time traveller setting off to kill her younger self. As discussed, no contradiction need ensue—this is prevented not by chaperones or mysterious forces, but by a run of ordinary occurrences in which the trigger falls off the time traveller’s gun, a gust of wind pushes her bullet off course, she slips on a banana peel, and so on. But now consider this run of ordinary occurrences. Whenever the time traveller contemplates auto-infanticide, someone nearby will drop a banana peel ready for her to slip on, or a bird will begin to fly so that it will be in the path of the time traveller’s bullet by the time she fires, and so on. In general, there will be a correlation between auto-infanticide attempts and foiling occurrences such as the presence of banana peels—and this correlation will be of the type that does not involve a direct causal connection between the correlated events or a common cause of both. But extensive correlations of this sort are, as we saw, extremely rare—so backwards time travel will happen about as often as you will see two people wear the same outfits to class every day of semester, without there being any causal connection between what one wears and what the other wears.

We can set out Horwich’s argument this way:

If time travel were ever to occur, we should see extensive uncaused correlations.
It is extremely unlikely that we should ever see extensive uncaused correlations.
Therefore time travel is extremely unlikely to occur.

The conclusion is not that time travel is impossible, but that we should treat it the way we treat the possibility of, say, tossing a fair coin and getting heads one thousand times in a row. As Price (1996, 278 n.7) puts it—in the context of endorsing Horwich’s conclusion: “the hypothesis of time travel can be made to imply propositions of arbitrarily low probability. This is not a classical reductio, but it is as close as science ever gets.”

Smith (1997) attacks both premisses of Horwich’s argument. Against the first premise, he argues that backwards time travel, in itself, does not entail extensive uncaused correlations. Rather, when we look more closely, we see that time travel scenarios involving extensive uncaused correlations always build in prior coincidences which are themselves highly unlikely. Against the second premise, he argues that, from the fact that we have never seen extensive uncaused correlations, it does not follow that we never shall. This is not inductive scepticism: let us assume (contra the inductive sceptic) that in the absence of any specific reason for thinking things should be different in the future, we are entitled to assume they will continue being the same; still we cannot dismiss a specific reason for thinking the future will be a certain way simply on the basis that things have never been that way in the past. You might reassure an anxious friend that the sun will certainly rise tomorrow because it always has in the past—but you cannot similarly refute an astronomer who claims to have discovered a specific reason for thinking that the earth will stop rotating overnight.

Sider (2002, 119–20) endorses Smith’s second objection. Dowe (2003) criticises Smith’s first objection, but agrees with the second, concluding overall that time travel has not been shown to be improbable. Ismael (2003) reaches a similar conclusion. Goddu (2007) criticises Smith’s first objection to Horwich. Further contributions to the debate include Arntzenius (2006), Smeenk and Wüthrich (2011, §2.2) and Elliott (2018). For other arguments to the same conclusion as Horwich’s—that time travel is improbable—see Ney (2000) and Effingham (2020).

Return again to the original version of the Grandfather paradox and Lewis’s ‘commonplace reasons’ response to it. This response engenders a further objection. The autoinfanticidal time traveller is attempting to do something impossible (render herself permanently dead from an age younger than her age at the time of the attempts). Suppose we accept that she will not succeed and that what will stop her is a succession of commonplace occurrences. The previous objection was that such a succession is improbable . The new objection is that the exclusion of the time traveler from successfully committing auto-infanticide is mysteriously inexplicable . The worry is as follows. Each particular event that foils the time traveller is explicable in a perfectly ordinary way; but the inevitable combination of these events amounts to a ring-fencing of the forbidden zone of autoinfanticide—and this ring-fencing is mystifying. It’s like a grand conspiracy to stop the time traveler from doing what she wants to do—and yet there are no conspirators: no time lords, no magical forces of logic. This is profoundly perplexing. Riggs (1997, 52) writes: “Lewis’s account may do for a once only attempt, but is untenable as a general explanation of Tim’s continual lack of success if he keeps on trying.” Ismael (2003, 308) writes: “Considered individually, there will be nothing anomalous in the explanations…It is almost irresistible to suppose, however, that there is something anomalous in the cases considered collectively, i.e., in our unfailing lack of success.” See also Gorovitz (1964, 366–7), Horwich (1987, 119–21) and Carroll (2010, 86).

There have been two different kinds of defense of time travel against the objection that it involves mysteriously inexplicable occurrences. Baron and Colyvan (2016, 70) agree with the objectors that a purely causal explanation of failure—e.g. Tim fails to kill Grandfather because first he slips on a banana peel, then his gun jams, and so on—is insufficient. However they argue that, in addition, Lewis offers a non-causal—a logical —explanation of failure: “What explains Tim’s failure to kill his grandfather, then, is something about logic; specifically: Tim fails to kill his grandfather because the law of non-contradiction holds.” Smith (2017) argues that the appearance of inexplicability is illusory. There are no scenarios satisfying the description ‘a time traveller commits autoinfanticide’ (or changes the past in any other way) because the description is self-contradictory (e.g. it involves the time traveller permanently dying at 20 and also being alive at 40). So whatever happens it will not be ‘that’. There is literally no way for the time traveller not to fail. Hence there is no need for—or even possibility of—a substantive explanation of why failure invariably occurs, and such failure is not perplexing.

3. Causation

Backwards time travel scenarios give rise to interesting issues concerning causation. In this section we examine two such issues.

Earlier we distinguished changing the past and affecting the past, and argued that while the former is impossible, backwards time travel need involve only the latter. Affecting the past would be an example of backwards causation (i.e. causation where the effect precedes its cause)—and it has been argued that this too is impossible, or at least problematic. [ 18 ] The classic argument against backwards causation is the bilking argument . [ 19 ] Faced with the claim that some event A causes an earlier event B , the proponent of the bilking objection recommends an attempt to decorrelate A and B —that is, to bring about A in cases in which B has not occurred, and to prevent A in cases in which B has occurred. If the attempt is successful, then B often occurs despite the subsequent nonoccurrence of A , and A often occurs without B occurring, and so A cannot be the cause of B . If, on the other hand, the attempt is unsuccessful—if, that is, A cannot be prevented when B has occurred, nor brought about when B has not occurred—then, it is argued, it must be B that is the cause of A , rather than vice versa.

The bilking procedure requires repeated manipulation of event A . Thus, it cannot get under way in cases in which A is either unrepeatable or unmanipulable. Furthermore, the procedure requires us to know whether or not B has occurred, prior to manipulating A —and thus, it cannot get under way in cases in which it cannot be known whether or not B has occurred until after the occurrence or nonoccurrence of A (Dummett, 1964). These three loopholes allow room for many claims of backwards causation that cannot be touched by the bilking argument, because the bilking procedure cannot be performed at all. But what about those cases in which it can be performed? If the procedure succeeds—that is, A and B are decorrelated—then the claim that A causes B is refuted, or at least weakened (depending upon the details of the case). But if the bilking attempt fails, it does not follow that it must be B that is the cause of A , rather than vice versa. Depending upon the situation, that B causes A might become a viable alternative to the hypothesis that A causes B —but there is no reason to think that this alternative must always be the superior one. For example, suppose that I see a photo of you in a paper dated well before your birth, accompanied by a report of your arrival from the future. I now try to bilk your upcoming time trip—but I slip on a banana peel while rushing to push you away from your time machine, my time travel horror stories only inspire you further, and so on. Or again, suppose that I know that you were not in Sydney yesterday. I now try to get you to go there in your time machine—but first I am struck by lightning, then I fall down a manhole, and so on. What does all this prove? Surely not that your arrival in the past causes your departure from the future. Depending upon the details of the case, it seems that we might well be entitled to describe it as involving backwards time travel and backwards causation. At least, if we are not so entitled, this must be because of other facts about the case: it would not follow simply from the repeated coincidental failures of my bilking attempts.

Backwards time travel would apparently allow for the possibility of causal loops, in which things come from nowhere. The things in question might be objects—imagine a time traveller who steals a time machine from the local museum in order to make his time trip and then donates the time machine to the same museum at the end of the trip (i.e. in the past). In this case the machine itself is never built by anyone—it simply exists. The things in question might be information—imagine a time traveller who explains the theory behind time travel to her younger self: theory that she herself knows only because it was explained to her in her youth by her time travelling older self. The things in question might be actions. Imagine a time traveller who visits his younger self. When he encounters his younger self, he suddenly has a vivid memory of being punched on the nose by a strange visitor. He realises that this is that very encounter—and resignedly proceeds to punch his younger self. Why did he do it? Because he knew that it would happen and so felt that he had to do it—but he only knew it would happen because he in fact did it. [ 20 ]

One might think that causal loops are impossible—and hence that insofar as backwards time travel entails such loops, it too is impossible. [ 21 ] There are two issues to consider here. First, does backwards time travel entail causal loops? Lewis (1976, 148) raises the question whether there must be causal loops whenever there is backwards causation; in response to the question, he says simply “I am not sure.” Mellor (1998, 131) appears to claim a positive answer to the question. [ 22 ] Hanley (2004, 130) defends a negative answer by telling a time travel story in which there is backwards time travel and backwards causation, but no causal loops. [ 23 ] Monton (2009) criticises Hanley’s counterexample, but also defends a negative answer via different counterexamples. Effingham (2020) too argues for a negative answer.

Second, are causal loops impossible, or in some other way objectionable? One objection is that causal loops are inexplicable . There have been two main kinds of response to this objection. One is to agree but deny that this is a problem. Lewis (1976, 149) accepts that a loop (as a whole) would be inexplicable—but thinks that this inexplicability (like that of the Big Bang or the decay of a tritium atom) is merely strange, not impossible. In a similar vein, Meyer (2012, 263) argues that if someone asked for an explanation of a loop (as a whole), “the blame would fall on the person asking the question, not on our inability to answer it.” The second kind of response (Hanley, 2004, §5) is to deny that (all) causal loops are inexplicable. A second objection to causal loops, due to Mellor (1998, ch.12), is that in such loops the chances of events would fail to be related to their frequencies in accordance with the law of large numbers. Berkovitz (2001) and Dowe (2001) both argue that Mellor’s objection fails to establish the impossibility of causal loops. [ 24 ] Effingham (2020) considers—and rebuts—some additional objections to the possibility of causal loops.

4. Time and Change

Gödel (1949a [1990a])—in which Gödel presents models of Einstein’s General Theory of Relativity in which there exist CTC’s—can well be regarded as initiating the modern academic literature on time travel, in both philosophy and physics. In a companion paper, Gödel discusses the significance of his results for more general issues in the philosophy of time (Gödel 1949b [1990b]). For the succeeding half century, the time travel literature focussed predominantly on objections to the possibility (or probability) of time travel. More recently, however, there has been renewed interest in the connections between time travel and more general issues in the metaphysics of time and change. We examine some of these in the present section. [ 25 ]

The first thing that we need to do is set up the various metaphysical positions whose relationships with time travel will then be discussed. Consider two metaphysical questions:

Are the past, present and future equally real?
Is there an objective flow or passage of time, and an objective now?

We can label some views on the first question as follows. Eternalism is the view that past and future times, objects and events are just as real as the present time and present events and objects. Nowism is the view that only the present time and present events and objects exist. Now-and-then-ism is the view that the past and present exist but the future does not. We can also label some views on the second question. The A-theory answers in the affirmative: the flow of time and division of events into past (before now), present (now) and future (after now) are objective features of reality (as opposed to mere features of our experience). Furthermore, they are linked: the objective flow of time arises from the movement, through time, of the objective now (from the past towards the future). The B-theory answers in the negative: while we certainly experience now as special, and time as flowing, the B-theory denies that what is going on here is that we are detecting objective features of reality in a way that corresponds transparently to how those features are in themselves. The flow of time and the now are not objective features of reality; they are merely features of our experience. By combining answers to our first and second questions we arrive at positions on the metaphysics of time such as: [ 26 ]

the block universe view: eternalism + B-theory
the moving spotlight view: eternalism + A-theory
the presentist view: nowism + A-theory
the growing block view: now-and-then-ism + A-theory.

So much for positions on time itself. Now for some views on temporal objects: objects that exist in (and, in general, change over) time. Three-dimensionalism is the view that persons, tables and other temporal objects are three-dimensional entities. On this view, what you see in the mirror is a whole person. [ 27 ] Tomorrow, when you look again, you will see the whole person again. On this view, persons and other temporal objects are wholly present at every time at which they exist. Four-dimensionalism is the view that persons, tables and other temporal objects are four-dimensional entities, extending through three dimensions of space and one dimension of time. On this view, what you see in the mirror is not a whole person: it is just a three-dimensional temporal part of a person. Tomorrow, when you look again, you will see a different such temporal part. Say that an object persists through time if it is around at some time and still around at a later time. Three- and four-dimensionalists agree that (some) objects persist, but they differ over how objects persist. According to three-dimensionalists, objects persist by enduring : an object persists from t 1 to t 2 by being wholly present at t 1 and t 2 and every instant in between. According to four-dimensionalists, objects persist by perduring : an object persists from t 1 to t 2 by having temporal parts at t 1 and t 2 and every instant in between. Perduring can be usefully compared with being extended in space: a road extends from Melbourne to Sydney not by being wholly located at every point in between, but by having a spatial part at every point in between.

It is natural to combine three-dimensionalism with presentism and four-dimensionalism with the block universe view—but other combinations of views are certainly possible.

Gödel (1949b [1990b]) argues from the possibility of time travel (more precisely, from the existence of solutions to the field equations of General Relativity in which there exist CTC’s) to the B-theory: that is, to the conclusion that there is no objective flow or passage of time and no objective now. Gödel begins by reviewing an argument from Special Relativity to the B-theory: because the notion of simultaneity becomes a relative one in Special Relativity, there is no room for the idea of an objective succession of “nows”. He then notes that this argument is disrupted in the context of General Relativity, because in models of the latter theory to date, the presence of matter does allow recovery of an objectively distinguished series of “nows”. Gödel then proposes a new model (Gödel 1949a [1990a]) in which no such recovery is possible. (This is the model that contains CTC’s.) Finally, he addresses the issue of how one can infer anything about the nonexistence of an objective flow of time in our universe from the existence of a merely possible universe in which there is no objectively distinguished series of “nows”. His main response is that while it would not be straightforwardly contradictory to suppose that the existence of an objective flow of time depends on the particular, contingent arrangement and motion of matter in the world, this would nevertheless be unsatisfactory. Responses to Gödel have been of two main kinds. Some have objected to the claim that there is no objective flow of time in his model universe (e.g. Savitt (2005); see also Savitt (1994)). Others have objected to the attempt to transfer conclusions about that model universe to our own universe (e.g. Earman (1995, 197–200); for a partial response to Earman see Belot (2005, §3.4)). [ 28 ]

Earlier we posed two questions:

Gödel’s argument is related to the second question. Let’s turn now to the first question. Godfrey-Smith (1980, 72) writes “The metaphysical picture which underlies time travel talk is that of the block universe [i.e. eternalism, in the terminology of the present entry], in which the world is conceived as extended in time as it is in space.” In his report on the Analysis problem to which Godfrey-Smith’s paper is a response, Harrison (1980, 67) replies that he would like an argument in support of this assertion. Here is an argument: [ 29 ]

A fundamental requirement for the possibility of time travel is the existence of the destination of the journey. That is, a journey into the past or the future would have to presuppose that the past or future were somehow real. (Grey, 1999, 56)

Dowe (2000, 442–5) responds that the destination does not have to exist at the time of departure: it only has to exist at the time of arrival—and this is quite compatible with non-eternalist views. And Keller and Nelson (2001, 338) argue that time travel is compatible with presentism:

There is four-dimensional [i.e. eternalist, in the terminology of the present entry] time-travel if the appropriate sorts of events occur at the appropriate sorts of times; events like people hopping into time-machines and disappearing, people reappearing with the right sorts of memories, and so on. But the presentist can have just the same patterns of events happening at just the same times. Or at least, it can be the case on the presentist model that the right sorts of events will happen, or did happen, or are happening, at the rights sorts of times. If it suffices for four-dimensionalist time-travel that Jennifer disappears in 2054 and appears in 1985 with the right sorts of memories, then why shouldn’t it suffice for presentist time-travel that Jennifer will disappear in 2054, and that she did appear in 1985 with the right sorts of memories?

Sider (2005) responds that there is still a problem reconciling presentism with time travel conceived in Lewis’s way: that conception of time travel requires that personal time is similar to external time—but presentists have trouble allowing this. Further contributions to the debate whether presentism—and other versions of the A-theory—are compatible with time travel include Monton (2003), Daniels (2012), Hall (2014) and Wasserman (2018) on the side of compatibility, and Miller (2005), Slater (2005), Miller (2008), Hales (2010) and Markosian (2020) on the side of incompatibility.

Leibniz’s Law says that if x = y (i.e. x and y are identical—one and the same entity) then x and y have exactly the same properties. There is a superficial conflict between this principle of logic and the fact that things change. If Bill is at one time thin and at another time not so—and yet it is the very same person both times—it looks as though the very same entity (Bill) both possesses and fails to possess the property of being thin. Three-dimensionalists and four-dimensionalists respond to this problem in different ways. According to the four-dimensionalist, what is thin is not Bill (who is a four-dimensional entity) but certain temporal parts of Bill; and what is not thin are other temporal parts of Bill. So there is no single entity that both possesses and fails to possess the property of being thin. Three-dimensionalists have several options. One is to deny that there are such properties as ‘thin’ (simpliciter): there are only temporally relativised properties such as ‘thin at time t ’. In that case, while Bill at t 1 and Bill at t 2 are the very same entity—Bill is wholly present at each time—there is no single property that this one entity both possesses and fails to possess: Bill possesses the property ‘thin at t 1 ’ and lacks the property ‘thin at t 2 ’. [ 30 ]

Now consider the case of a time traveller Ben who encounters his younger self at time t . Suppose that the younger self is thin and the older self not so. The four-dimensionalist can accommodate this scenario easily. Just as before, what we have are two different three-dimensional parts of the same four-dimensional entity, one of which possesses the property ‘thin’ and the other of which does not. The three-dimensionalist, however, faces a problem. Even if we relativise properties to times, we still get the contradiction that Ben possesses the property ‘thin at t ’ and also lacks that very same property. [ 31 ] There are several possible options for the three-dimensionalist here. One is to relativise properties not to external times but to personal times (Horwich, 1975, 434–5); another is to relativise properties to spatial locations as well as to times (or simply to spacetime points). Sider (2001, 101–6) criticises both options (and others besides), concluding that time travel is incompatible with three-dimensionalism. Markosian (2004) responds to Sider’s argument; [ 32 ] Miller (2006) also responds to Sider and argues for the compatibility of time travel and endurantism; Gilmore (2007) seeks to weaken the case against endurantism by constructing analogous arguments against perdurantism. Simon (2005) finds problems with Sider’s arguments, but presents different arguments for the same conclusion; Effingham and Robson (2007) and Benovsky (2011) also offer new arguments for this conclusion. For further discussion see Wasserman (2018) and Effingham (2020). [ 33 ]

We have seen arguments to the conclusions that time travel is impossible, improbable and inexplicable. Here’s an argument to the conclusion that backwards time travel simply will not occur. If backwards time travel is ever going to occur, we would already have seen the time travellers—but we have seen none such. [ 34 ] The argument is a weak one. [ 35 ] For a start, it is perhaps conceivable that time travellers have already visited the Earth [ 36 ] —but even granting that they have not, this is still compatible with the future actuality of backwards time travel. First, it may be that time travel is very expensive, difficult or dangerous—or for some other reason quite rare—and that by the time it is available, our present period of history is insufficiently high on the list of interesting destinations. Second, it may be—and indeed existing proposals in the physics literature have this feature—that backwards time travel works by creating a CTC that lies entirely in the future: in this case, backwards time travel becomes possible after the creation of the CTC, but travel to a time earlier than the time at which the CTC is created is not possible. [ 37 ]

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Is Time Travel Possible?

We all travel in time! We travel one year in time between birthdays, for example. And we are all traveling in time at approximately the same speed: 1 second per second.

We typically experience time at one second per second. Credit: NASA/JPL-Caltech

NASA's space telescopes also give us a way to look back in time. Telescopes help us see stars and galaxies that are very far away . It takes a long time for the light from faraway galaxies to reach us. So, when we look into the sky with a telescope, we are seeing what those stars and galaxies looked like a very long time ago.

However, when we think of the phrase "time travel," we are usually thinking of traveling faster than 1 second per second. That kind of time travel sounds like something you'd only see in movies or science fiction books. Could it be real? Science says yes!

Image of galaxies, taken by the Hubble Space Telescope.

This image from the Hubble Space Telescope shows galaxies that are very far away as they existed a very long time ago. Credit: NASA, ESA and R. Thompson (Univ. Arizona)

How do we know that time travel is possible?

More than 100 years ago, a famous scientist named Albert Einstein came up with an idea about how time works. He called it relativity. This theory says that time and space are linked together. Einstein also said our universe has a speed limit: nothing can travel faster than the speed of light (186,000 miles per second).

Einstein's theory of relativity says that space and time are linked together. Credit: NASA/JPL-Caltech

What does this mean for time travel? Well, according to this theory, the faster you travel, the slower you experience time. Scientists have done some experiments to show that this is true.

For example, there was an experiment that used two clocks set to the exact same time. One clock stayed on Earth, while the other flew in an airplane (going in the same direction Earth rotates).

After the airplane flew around the world, scientists compared the two clocks. The clock on the fast-moving airplane was slightly behind the clock on the ground. So, the clock on the airplane was traveling slightly slower in time than 1 second per second.

Credit: NASA/JPL-Caltech

Can we use time travel in everyday life?

We can't use a time machine to travel hundreds of years into the past or future. That kind of time travel only happens in books and movies. But the math of time travel does affect the things we use every day.

For example, we use GPS satellites to help us figure out how to get to new places. (Check out our video about how GPS satellites work .) NASA scientists also use a high-accuracy version of GPS to keep track of where satellites are in space. But did you know that GPS relies on time-travel calculations to help you get around town?

GPS satellites orbit around Earth very quickly at about 8,700 miles (14,000 kilometers) per hour. This slows down GPS satellite clocks by a small fraction of a second (similar to the airplane example above).

Illustration of GPS satellites orbiting around Earth

GPS satellites orbit around Earth at about 8,700 miles (14,000 kilometers) per hour. Credit: GPS.gov

However, the satellites are also orbiting Earth about 12,550 miles (20,200 km) above the surface. This actually speeds up GPS satellite clocks by a slighter larger fraction of a second.

Here's how: Einstein's theory also says that gravity curves space and time, causing the passage of time to slow down. High up where the satellites orbit, Earth's gravity is much weaker. This causes the clocks on GPS satellites to run faster than clocks on the ground.

The combined result is that the clocks on GPS satellites experience time at a rate slightly faster than 1 second per second. Luckily, scientists can use math to correct these differences in time.

Illustration of a hand holding a phone with a maps application active.

If scientists didn't correct the GPS clocks, there would be big problems. GPS satellites wouldn't be able to correctly calculate their position or yours. The errors would add up to a few miles each day, which is a big deal. GPS maps might think your home is nowhere near where it actually is!

In Summary:

Yes, time travel is indeed a real thing. But it's not quite what you've probably seen in the movies. Under certain conditions, it is possible to experience time passing at a different rate than 1 second per second. And there are important reasons why we need to understand this real-world form of time travel.

If you liked this, you may like:

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Published: 04 October 2016

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A brief history of time travel

Dave Goldberg 1

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Science in culture

Time Travel: A History

James Gleick

In his brisk and entertaining new book, Time Travel: A History , James Gleick serves as an enthusiastic guide through the fourth dimension as seen in literature and popular culture. I spoke with Gleick to discuss his book, the interface between science and science fiction and what makes genuinely compelling time travel.

Gleick begins his story around the turn of the twentieth century, which saw both H. G. Wells's publication of The Time Machine and, not entirely coincidentally, Albert Einstein's annus mirabilis papers. Wells wasn't a scientist, and nobody — least of all Gleick — would make the argument that The Time Machine presaged special relativity, but he argues that language itself made spacetime almost an inevitable concept; we use the same word for the flow of time and the flow of a river, for example. “Physicists didn't invent that analogy; it was partly built into the language because we don't have words for everything. But the words connecting space and time became more powerful over time.”

The nineteenth century was a golden age of geology and Wells in particular was fascinated by it. There is a very literal sense in which the physical strata of Earth represent movement through time. That, along with the synchronization of clocks required for successful railroads, started many thinkers on the path of considering what time really is. Gleick notes, “Wells's hero, the time traveller, makes a speech explaining why time travel is possible in a way that to modern ears is almost comically pedantic. We can see that his vision of the Universe is almost standard — it's Einstein's version of the Universe”.

But time as a river, or a dimension or any of the familiar analogies is more than simple language at play. We know, and Einstein showed, that space and time really can be rotated into one another with a suitable choice of frame. Wells's innovation was to consider seriously the premise of freely traversing time as we would any other dimension.

Wells is a seminal figure in the development of fictional time travel, but he wasn't the first. Mark Twain's A Connecticut Yankee in King Arthur's Court , for example, predated The Time Machine by six years. But Twain's Connecticut Yankee is more of a tourist than what we now consider a time traveller.

Gleick makes the pitch that the precursors of modern time travel include many ideas that we wouldn't call time travel at all: sleeping into the future, for example, in the tradition of Rip Van Winkle or in prophecies going back to the ancients. In the early decades of the twentieth century, the time capsule fad represented a way of speaking directly to the future — albeit only in one dimension.

Wells's time traveller, however, wasn't simply a passive observer. He could affect the future (and Wells seemed to be uniquely interested in travelling into the future), prompting Gleick to propose a parlour game similar to the 'flight or invisibility?' litmus test for superpowers: “if you had one shot with a time machine, would you go into the future or the past, provided you could go and return safely?”

The future is full of promise, but in the past you could — perhaps — fix your mistakes. Gleick's tour of the development of what are by now are familiar paradoxes brings into focus the giants of early science fiction. One example is Ray Bradbury's A Sound of Thunder , which showed that changes in the past (in the story, the crushing of a butterfly in the Jurassic) can lead inexorably to dramatic changes in the present.

Temporal manipulations can create paradoxes, the most famous of which amounts to the fact that you can't kill your grandfather and prevent your own birth — or can you? From a storytelling perspective, time travel, or at least backwards time travel, seems to preclude the possibility of free will.

In the 1980s, the Russian physicist Igor Novikov put forth what is now known as the 'self-consistency conjecture', which posited, in short, that the probability of inconsistent histories in closed time-like curves was exactly zero. Quantum events should play themselves out the same way the second time around. Gleick notes that “this was why writing the book was so much fun. Watching first the science fiction writers and then the physicists grapple with these questions. What we love about science is the very way it undermines our common sense and it's a great joy whenever it happens.” He cites classic sci-fi movies like The Terminator, 12 Monkeys (itself a remake of La Jetée , a film he lovingly describes in detail in his book) and, in a particularly neat resolution, 'Blink' (an episode of the classic sci-fi series Doctor Who ).

The 'trick' in great time travel literature becomes the way in which the author closes the loop. As Gleick puts it, “the job of a good time travel writer is to explore the paradox by taking it seriously ... but when you go back and think about it, you can see the trick”.

What distinguishes Time Travel: A History from other books more focused on the philosophy or physics of time travel is that Gleick allows himself into the realm of the aesthetic. It is irrelevant whether the physical mechanism for time travel is driven by a steampunk bicycle or a wormhole — you have to believe in the dramatic stakes.

As to the practical possibility of time travel, Gleick is something of a sceptic. Common sense, he argues, suggests that the past really is immutable, no matter how clever the theoretical models that imply otherwise. And despite the apparent symmetry of the microscopic laws of physics, there really is, he argues, something different about the future and the past. “The future hasn't been written yet. When did that become controversial?”

DAVE GOLDBERG Dave Goldberg is in the Department of Physics, Drexel University, Philadelphia, Pennsylvania 19104, USA. e-mail: [email protected]

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A Brief History Of Time Travel

As humans, we have always been fascinated with the concept of time travel. The idea of being able to journey through different eras and witness history first-hand has captivated our imaginations for centuries. From ancient myths and folklore to modern-day science fiction, time travel has remained a popular topic in various forms of media.

In this article, we will explore the history of time travel - from its earliest mythological roots to modern scientific theories and popular culture representations. We will also delve into the philosophical and ethical implications of time travel, as well as recent developments in technology that bring us closer to making this once-fictional concept a reality. Join us on this journey through time as we uncover the secrets behind one of humanity's most enduring fantasies.

Can we time travel? A theoretical physicist provides some answers

Emeritus professor, Physics, Carleton University

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Time travel makes regular appearances in popular culture, with innumerable time travel storylines in movies, television and literature. But it is a surprisingly old idea: one can argue that the Greek tragedy Oedipus Rex , written by Sophocles over 2,500 years ago, is the first time travel story .

But is time travel in fact possible? Given the popularity of the concept, this is a legitimate question. As a theoretical physicist, I find that there are several possible answers to this question, not all of which are contradictory.

The simplest answer is that time travel cannot be possible because if it was, we would already be doing it. One can argue that it is forbidden by the laws of physics, like the second law of thermodynamics or relativity . There are also technical challenges: it might be possible but would involve vast amounts of energy.

There is also the matter of time-travel paradoxes; we can — hypothetically — resolve these if free will is an illusion, if many worlds exist or if the past can only be witnessed but not experienced. Perhaps time travel is impossible simply because time must flow in a linear manner and we have no control over it, or perhaps time is an illusion and time travel is irrelevant.

a woman stands among a crowd of people moving around her

Laws of physics

Since Albert Einstein’s theory of relativity — which describes the nature of time, space and gravity — is our most profound theory of time, we would like to think that time travel is forbidden by relativity. Unfortunately, one of his colleagues from the Institute for Advanced Study, Kurt Gödel, invented a universe in which time travel was not just possible, but the past and future were inextricably tangled.

We can actually design time machines , but most of these (in principle) successful proposals require negative energy , or negative mass, which does not seem to exist in our universe. If you drop a tennis ball of negative mass, it will fall upwards. This argument is rather unsatisfactory, since it explains why we cannot time travel in practice only by involving another idea — that of negative energy or mass — that we do not really understand.

Mathematical physicist Frank Tipler conceptualized a time machine that does not involve negative mass, but requires more energy than exists in the universe .

Time travel also violates the second law of thermodynamics , which states that entropy or randomness must always increase. Time can only move in one direction — in other words, you cannot unscramble an egg. More specifically, by travelling into the past we are going from now (a high entropy state) into the past, which must have lower entropy.

This argument originated with the English cosmologist Arthur Eddington , and is at best incomplete. Perhaps it stops you travelling into the past, but it says nothing about time travel into the future. In practice, it is just as hard for me to travel to next Thursday as it is to travel to last Thursday.

Resolving paradoxes

There is no doubt that if we could time travel freely, we run into the paradoxes. The best known is the “ grandfather paradox ”: one could hypothetically use a time machine to travel to the past and murder their grandfather before their father’s conception, thereby eliminating the possibility of their own birth. Logically, you cannot both exist and not exist.

Read more: Time travel could be possible, but only with parallel timelines

Kurt Vonnegut’s anti-war novel Slaughterhouse-Five , published in 1969, describes how to evade the grandfather paradox. If free will simply does not exist, it is not possible to kill one’s grandfather in the past, since he was not killed in the past. The novel’s protagonist, Billy Pilgrim, can only travel to other points on his world line (the timeline he exists in), but not to any other point in space-time, so he could not even contemplate killing his grandfather.

The universe in Slaughterhouse-Five is consistent with everything we know. The second law of thermodynamics works perfectly well within it and there is no conflict with relativity. But it is inconsistent with some things we believe in, like free will — you can observe the past, like watching a movie, but you cannot interfere with the actions of people in it.

Could we allow for actual modifications of the past, so that we could go back and murder our grandfather — or Hitler ? There are several multiverse theories that suppose that there are many timelines for different universes. This is also an old idea: in Charles Dickens’ A Christmas Carol , Ebeneezer Scrooge experiences two alternative timelines, one of which leads to a shameful death and the other to happiness.

Time is a river

Roman emperor Marcus Aurelius wrote that:

“ Time is like a river made up of the events which happen , and a violent stream; for as soon as a thing has been seen, it is carried away, and another comes in its place, and this will be carried away too.”

We can imagine that time does flow past every point in the universe, like a river around a rock. But it is difficult to make the idea precise. A flow is a rate of change — the flow of a river is the amount of water that passes a specific length in a given time. Hence if time is a flow, it is at the rate of one second per second, which is not a very useful insight.

Theoretical physicist Stephen Hawking suggested that a “ chronology protection conjecture ” must exist, an as-yet-unknown physical principle that forbids time travel. Hawking’s concept originates from the idea that we cannot know what goes on inside a black hole, because we cannot get information out of it. But this argument is redundant: we cannot time travel because we cannot time travel!

Researchers are investigating a more fundamental theory, where time and space “emerge” from something else. This is referred to as quantum gravity , but unfortunately it does not exist yet.

So is time travel possible? Probably not, but we don’t know for sure!

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A Brief History of Time Travel (in Movies)

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From Men In Black III to Back to the Future to Planet of the Apes , films that voyage through the ages face internal consistency problems—and tap into the human desire to change fate.

If ever a movie earned its time-travel plotline, it's Men in Black 3 , which attempts to revive a movie franchise largely forgotten by audiences after its disappointing second entry. Men in Black 3 sees Will Smith's Agent J going back to the 1960s to save partner Agent K (Tommy Lee Jones in the present, Josh Brolin in the past), and mines its late-'60s setting for jokes both obvious (hippies, Andy Warhol) and subtle (Rick Baker's new alien designs, which are derived from the style of '60s science fiction).

But if time travel, as the Men in Black would have it, is "illegal throughout the universe," cinema is full of lawbreakers. It's been 10 years since the last Men in Black movie, but nearly 100 years since the first time-travel film hit movie theaters. There are so many variations on turning the clock forwards and backwards in cinema that it's difficult to say these films even belong to a unified "genre." But every time-traveling movie has, in its own way, had to overcome the mind-bending logic problems inherent in its premise. And each, too, has played on a universal, if vain, human desire to experience a world that's entirely unavailable to us—and perhaps to change things in our own.

Though most would cite H.G. Wells's 1895 novel The Time Machine as the progenitor of the modern time-travel story, the author wrote an even earlier one, "The Chronic Argonauts," in 1888. Sandwiched between Wells's two time-machine stories was the other founding text of the genre: Mark Twain's 1889 satire A Connecticut Yankee in King Arthur's Court . Unlike Wells, who always put at least a cursory effort into the science of his science fiction, Twain was more interested in what a time traveler would do than in how he got there; his Connecticut Yankee awakens in Camelot times after being knocked out by a crowbar.

It took a long time for the time-travel film to escape Wells and Twain's sci-fi shadows. The first three notable entries in the genre were adaptations of A Connecticut Yankee in King Arthur's Court : a 1921 silent, a 1931 talkie, and a 1949 musical. George Pal's classic 1960 adaptation of The Time Machine was the first time-travel film to win an Oscar (for best visual effects). But despite these successes, time travel remained on the fringes of popular culture, only appearing as a plot device in adaptations like Planet of the Apes and Slaughterhouse-Five , or the occasional B-movie like The Time Travelers or Journey to the Center of Time .

Story continues below

The fact that it took so long for a non-adapted time-travel story to become a mainstream hit is a testament to how difficult films like these are to write. Every time-travel tale needs to establish its own internally consistent set of rules, and hardcore genre fans—a notoriously pedantic bunch—will tear apart any story that fails to do so. (It's not for nothing that the Wikipedia page on "Predestination paradoxes in popular culture" alone is over 21,000 words long.) It wasn't until the early 1980s that filmmakers like James Cameron ( The Terminator ), and Robert Zemeckis ( Back to the Future ) discovered an ingenious solution to the near-impossibility of writing a sensical time-travel story: Write a time travel story that's so much fun mainstream audiences won't care about consistency.

MORE ON MOVIES

Despite the considerable differences in their plotlines and executions, Cameron and Zemeckis's back-to-back time-travel films were massive hits, spawning franchises that are unquestionably the genre's best. They succeeded, in part, because they found the balance between science—enough, in fact, to keep diehard genre fans working out its logic for decades—and story. And once the time travel genre was unwedded from its prickly reputation, Hollywood began to apply it to every kind of movie imaginable. It would be impossible to name all the notable time-traveling films released over the past century (though I've done my best in the slideshow above), but the years following The Terminator and Back to the Future saw everything from time-travel dramedys ( Peggy Sue Got Married ) to time-travel horror films ( Warlock ), time-travel romcoms ( Kate & Leopold ) to time-travel stoner films (The Bill & Ted films). Last year, Woody Allen's decade-hopping Midnight in Paris earned a nomination for Best Picture—the first in the genre to do so.

It's easy to see why these movies endure. Who hasn't day dreamed about knowing what's to come or going back and changing what's happened? By visiting the past, you learn where you came from; by visiting the future, you learn where you're going—and even if you return to the time you came from, your experiences have changed you. In the end, that's the real magic of the time-travel genre and the reason it's such a reliable box-office draw. All movies promise to take you away from your normal life and show you something new, but no genre does it quite so literally—or so well.

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A Brief History of Time Travel Literature

Yesterday, Stephen King’s newest work, 11/22/63 , a novel about a man who travels back in time via a storeroom to stop the JFK assassination, hit shelves. Inspired by this newest addition to the time travel literature genre, we got to thinking about a few of our favorite time travel stories, and particularly about all of the different ways those fictional mortals manage to thrust themselves back and forth in space-time. From our vantage, there are a few types of time travel that we see used over and over again: mechanical (time machines and the like), portal-based (stepping through some sort of floating hole in the space-time continuum), fantastical (ghosts or other unbelievable phenomena), magical/item-based (some sort of artifact that holds the power of time travel), and the simply unexplained (because why does it matter? Get to the cool future stuff already). There are hundreds of novels and short stories about or involving time travel, so these are a few of our favorites, plucked both from the beginnings of the genre and from contemporary literature.

The Time Machine , H.G. Wells, 1895 – Mechanical

Though not the first instance of time travel in literature, and not even the first example of a time machine (that honor goes to Enrique Gaspar y Rimbau’s 1887 novel El Anacronopete ), this is the novel that really brought time travel to the forefront of the public’s imagination. It makes sense, for while Wells didn’t dream up the concept, he did coin the term ‘time machine,’ and he also was the first to cement the idea of a machine that allows the user to travel back and forward purposefully, as opposed to randomly.

How to Live Safely in a Science Fictional Universe , Charles Yu, 2010 – Mechanical

In Yu’s meta-science fictional novel, the protagonist (also called Charles Yu) is a time machine repairman who lives in his own time machine. Like many protagonists of time travel novels, he catches himself in a time loop by shooting his future self, and tries to escape his own self-inflicted fate by cycling through time-space, while reflecting on his life, always trying to “keep stalling, see how long you can keep expanding the infinitely expandable moment.”

“ By His Bootstraps ,” Robert A. Heinlein, 1941 – Portal-based

This short story by one of the great masters of science fiction was originally published in the October 1941 issue of Astounding Science Fiction under the pen name Anson MacDonald. In the story, Bob is finishing up his thesis on — what else — time travel, when he is interrupted by a man named Joe, who declares that he has come from the future via a ‘Time Gate’ and asks him to come through. Before he can, another man appears, and a fight ensues. Needless to say, if you’re at all familiar with this genre, but all are versions of Bob from one point in time or another, and the story continues with Bob navigating his way through the time tangle, going back and forth through the gate that leads thirty thousand years in the future.

11/22/63 , Stephen King, 2011 – Portal-based

An example of an alternate history style time travel novel, thirty five year old high-school English teacher Jake Epping is leading an ordinary life when his friend Al, who runs the local diner, revelas that his storeroom is a portal to 1958 and sets Jake on a mission to prevent the JFK assassination. Though this is not even the first novel to deal with the JFK assassination via time travel, it sure is a good one.

A Christmas Carol , Charles Dickens, 1843 – Fantastical

If you’re anything like us, when you first read Charles Dickens’ famous tale of Ebenezer Scrooge, you didn’t even think of it as a time travel story. But time travel it is — Scrooge travels through space and time, visiting both his past and his future. Sure, he’s being lead about by ghosts, but the idea is the same — this greater understanding of the universe and the way things link to each other changes Scrooge’s mind and actions.

The Time Traveler’s Wife , Audrey Niffenegger, 2003 – Fantastical

Though the technical explanation for Henry DeTamble’s time travelling is a genetic disorder they call ‘Chrono-Displacement,’ the concept is so far-fetched that we have to put this in the ‘fantastical’ category. The time-travelling in this book is pretty interesting, however, because it’s involuntary — Henry can’t control when he will travel to, or how long he will stay in each time period, though it appears that his time travelling is sometimes brought on by stress. Now there’s a reason to relax if we’ve ever heard one.

Outlander , Diana Gabaldon, 1992 – Magical item-based

Another time travel-based romance novel, the first of a series of seven, Claire journeys from 1945 to the 18th century via a set of mystical standing stones on a hill in Scotland. She tends the wounds of a young man using her 20th century medical knowledge and nursing ability. Obviously, they fall in love. Swoon!

Harry Potter and the Prisoner of Azkaban , J.K. Rowling, 1999 – Magical item-based

Though this installment of Harry Potter can’t be classified as a time travel novel in its own right, time travel plays a huge part in the plot, so we’re counting it. Because she is such an epic nerd, Hermione is given a ‘time turner’ that will allow her ‘do hours over’ in order to take an extra-full course load. It’s an interesting and pretty unusual artifact in the Harry Potter universe — nothing about the world suggests that time travel should be possible, and it’s never really mentioned again. However, it’s magic, so who are we to say. Ultimately, Hermione, Harry and Ron must use the time turner to save an innocent man and secure his escape. It’s all carried off quite nicely.

A Connecticut Yankee in King Arthur’s Court , Mark Twain, 1889 – Basically unexplained

In A Connecticut Yankee in King Arthur’s Court , Hank Morgan, a regular guy living in Hartford, Connecticut in the 19th century, gets hit on the head with a crowbar (by a man named Hercules, no less) and wakes up in Camelot. This novel is one of the first to revolve around the idea of a character from the future introducing his knowledge and technology to a past civilization.

Slaughterhouse Five , Kurt Vonnegut, 1972 – Basically unexplained

In Vonnegut’s satirical novel about World War II, American soldier Billy Pilgrim has become “unstuck in time,” which causes him to experience the different events in his life non-sequentially and sometimes more than once. Thus, he is able to experience his death before his actual death, leaving him rather fatalistic. He is abducted by aliens, the Tralfamadorians, one of whom tells him, “I’ve visited thirty-one inhabited planets in the universe . . . Only on Earth is there any talk of free will.” Instead, the Tralfamadorians have seen their lives in their entirety, and believe that everything simultaneously exists, confusing the very notion of time, stuck or unstuck. So it goes.

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The History of Time Travel

A fictional documentary about the creation of the worlds first time machine, the men who created it, and the unintended ramifications it has on world events. A fictional documentary about the creation of the worlds first time machine, the men who created it, and the unintended ramifications it has on world events. A fictional documentary about the creation of the worlds first time machine, the men who created it, and the unintended ramifications it has on world events.

Ricky Kennedy
Stephen Adami
Krista Ales
Valerie Black
86 User reviews
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Richard Reenactor
Dr. Vanessa Byers
Anne Reenactor
CIA Agent #2
Gen. Douglas Sanborn
Soviet Scientist
(as Peter Calvin)
Aden Reenactor (Age 5)
Dr. Edward Yarborough
Richard Page
Aden Reenactor
Richard Reenactor (Age 53)
CIA Agent #1
Jim North, News Anchor
Richard Reenactor (Age 14)

Edward Page (Younger) …
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Trivia The mug shot of Edward lists his number as 208241138. If you assign the numbers to letters of the alphabet, you get 20=T, 8=H, and 24=X. THX-1138
Goofs When Richard goes back to inoculate his mother against polio, he brings booster shots. However, they never explain who or how the booster shots were administered. Either Richard had to stay until she was at least 4 (last booster age group for Polio) or someone had to have been given the booster shots and been complicit in providing them once Richard went back to his time.

[first lines]

Narrator : You're watching History Television.

Narrator : [clock ticking loudly] In 1895, writer H.G. Wells published his science fiction masterpiece, The Time Machine. This novel would be one in a long line of literature, motion pictures, and television shows, depicting man breaking the laws of time and space, to travel beyond his present existence.

Dr. Edward Yarborough : One of the great struggles, if not the greatest struggle, has been man versus time. I mean, we always want more.

Dr. Adam Lindquist : [on park bench] We are prisoners to time. Mankind has always been fascinated with the idea of escaping from it.

Kevin Ulrich : [at outdoor cafe] To be able to go back in time and fix a mistake, or change the outcome of a future event, it's a tantalizing prospect.

Dr. Jack Fincher : [in classroom] Could it even be possible? Well, what did Einstein think?

Connections References Somewhere in Time (1980)

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October 25, 2014 (Brazil)
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Runtime 1 hour 12 minutes

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Arrival/Departure History Now Available on I-94 Webpage

Customs and Border Protection launched a new webpage on May 1 that offers nonimmigrant U.S. visitors access to their I-94 arrival/departure record and their arrival/departure history.

The new CBP webpage allows nonimmigrant travelers to access arrival/departure records going back five years from the request date. This electronic travel-history function means that travelers may no longer need to file Freedom of Information Act requests to receive their arrival/departure history, greatly speeding their process. Travelers will have electronic access to the date and port of entry of their arrivals and departures.

When travelers visit the I-94 webpage they can retrieve their I-94 arrival/departure record number and five-year travel history by entering the required name, date of birth, and passport information.

Clicking on “Get Most Recent I-94” will return the I-94 number, most recent date of entry, class of admission and admit-until date. The information does not reflect changes of status, extension of stay or adjustments of status granted by U.S. Citizenship and Immigration Services. Travelers then have the option to print the record.

Clicking on “Get Travel History” will return their five-year travel history based on their I-94 records, which they also can print.

Travelers can also cancel pending Freedom of Information Act requests for travel history information—after they have received the information from the new website—by adding their FOIA Request Number and clicking on “Request FOIA Cancellation” button.

CBP began the online version of Form I-94 in April 2013. The positive public response to that streamlining prompted the agency to offer travel histories online as well.

If a traveler has lost a paper form I-94 that was issued prior to the online system and the record is not available online, the traveler can file a Form I-102, Application for Replacement/Initial Non-Immigrant Arrival-Departure Document, with U.S. Citizenship and Immigration Services.

U.S. Customs and Border Protection is the unified border agency within the Department of Homeland Security charged with the management, control and protection of our nation's borders at and between the official ports of entry. CBP is charged with keeping terrorists and terrorist weapons out of the country while enforcing hundreds of U.S. laws.

1.21 Gigawatts: The History of Time Travel in Cinema

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In some ways, the cinema is the closest thing we can experience to travelling through time – certainly the closest of any art form. In the dark room of a movie theatre, an audience can be transported to the distant past or spectacular visions of the future, and even in watching films from the 30’s and 40’s we can look at the lives and faces of people who died many years ago.

Time travel became popular as a literary device with HG Well’s The Time Machine – published in 1895, the same year that the Lumière Brothers made Arrival of a Train at La Ciotat . So time travel and cinema entered the public consciousness at the same time, and it has a long and fascinating history as a cinematic device. While rooted in science fiction, it has flitted around a variety of genres and even today filmmakers are exploring new ways to tell stories with it. Time travel is one of the most popular and interesting tropes in cinema and in this article we’ll look at how it’s developed through, well, time.

The earliest example of time travel in cinema dates to a 1921 adaptation of the Mark Twain story A Connecticut Yankee in King Arthur’s Court , of which only 3 of 8 original reels remain today. The film shows an American who dreams he is transported back to the time of King Arthur and defeats his foes using his contemporary knowledge.

The success of this silent inspired a sound remake in 1931 and a musical starring Bing Crosby in 1949. A Connecticut Yankee set the formula for other travel films of this era – the hero is typically whisked back against his own will to the past, where he engages in adventures and falls in love with a beautiful woman. Examples include I’ll Never Forget You (1951) and Berkeley Square (1933), which both send their hero to the 18th century.

It’s clear to see the appeal for audiences of the time, who could find new enjoyment through identifying with a contemporary protagonist in the for the escapist historical adventures that were popular at the time. At this point, then, the time travel itself was merely a device to get the character into the period setting, and fairly unimportant to the plot. These early experiments were firmly in the realm of fantasy – but this would change with the rise of science fiction in the 1950’s and beyond.

Developing ideas

The first year of the 60’s saw one of the most significant time travel films: George Pal ‘s adaptation of The Time Machine , the novel that started it all. The Victorian setting of the original novel remains, as a British inventor (named H.G. Wells in tribute) travels to the year 802,701, where far-future human descendants are hunted by subterranean Morlocks. The Time Machine was in some ways hugely ahead of its time, most significantly in the Oscar-winning visual effects, which use a combination of time-lapse photography and stop motion animation to depict flowers blooming, candles melting and the sun arcing across the sky in a matter of seconds.

Here we can see the visual potential of the time travel film come to fruition, in a way that only the cinema medium can provide. But more importantly Pal ‘s film updated the novel to provide an ominous social commentary, as Wells witnesses a nuclear holocaust on his journey to the future – dated at 1966, just 6 years after the film’s actual release. This, then, was an early example of using time travel to say something about the present; in this case, the fear of nuclear annihilation at the height of the Cold War.

A similar concept can be seen in a lesser known piece, the experimental French film La Jetee (1962). In this 28 minute short, which is constructed almost entirely from a series of photographs, a man from a post-apocalyptic Paris is chosen to be sent back before World War Three to warn the people of the past about the future. A key inspiration for the plot of Terry Gilliam’s Twelve Monkeys, it remains one of world cinema’s first and most significant forays into time travel.

Time travel breaks out

The 70’s were something of a bleak era: Wikipedia lists just seven time travel films for the whole decade, and two are sequels to Planet of the Apes , in which time travel is only used incidentally. But the 1980’s saw an explosion of popularity for the genre, and many of its most famous movies come from this time. Much of this stems from the huge success of 1984’s The Terminator .

The Terminator (1984) - source: Orion Pictures

The iconic Terminator character is what launched the careers of James Cameron and Arnold Schwarzenegger , which may be a good or terrible thing for the history of cinema, but the inventive plot – a robot from the future sent back to kill the future mother of a resistance fighter -showed us that the protagonist doesn’t have to travel at all; it’s the antagonist from a future environment who arrives in the present. The Terminator was released just months before one of the biggest films and franchises of the decade became perhaps the definitive image of time travel on screen: the still ridiculously enjoyable Back to the Future .

Robert Zemeckis and Bob Gale mined the comic potential of the genre by sending an 80’s teenager back to 1955 – via, of course, a beaten up DeLorean – where he attracts the friendship of his geeky dad and the romantic attention of his mother. It’s the culture clash that results from a gap of 30 years, instead of hundreds, that makes this film so effective; far away enough to be alien, but close enough to be recognisable. And despite being firmly entrenched in 80’s culture, the film manages to avoid feeling dated by embracing the atmosphere of the decade so well that it feels like a loving tribute rather than what was, at the time, present day. The appeal of seeing Marty McFly interacting with all the 50’s stereotypes and considering how you would react to watching your own dad get bullied or your own mother trying to flirt with you turned Back to the Future into one of the most successful films of the 80’s.

The effect of this success was instant, inspiring other films to use time travel as a device for comedy rather than adventure, or simply to spice up existing concepts and tropes. High school comedy Peggy Sue Got Married (directed by Francis Ford Coppola of all people) and slacker cult classic Bill and Ted’s Excellent Adventure were huge hits; Star Trek IV saw the crew of the Enterprise beam down to 1986. Meanwhile both Terminator and Back to the Future were establishing themselves in popular culture with a slew of sequels – many consider Terminator 2 to be even better than the original, and Back to the Future Part 2 was so popular that Marty and Doc’s visit to 2015 is going to be immortalised all year.

Present Day

After time travel became such a popular plot device in mainstream cinema in the 80’s, the films of the next few decades continued to explore more inventive and artful ways to use it. The previously mentioned Twelve Monkeys took the idea of a time traveller coming to warn us of the future, only to be assumed insane; Shane Carruth’s impenetrable Primer , about an accidentally created time machine and shot for just $7,000, has earned a reputation as one of the most cerebral and confusing science fiction films ever.

So where does it go from here? Time travel is being increasingly used in modern cinema – from thrillers like Source Code and Edge of Tomorrow , which use the concept of time loops, the protagonist reliving the same period of time repeatedly, blockbusters like X-Men: Days of Future Past and even Woody Allen comedies (2011’s Oscar winning Midnight in Paris ).

Edge of Tomorrow (2014) - source: Warner Bros. Pictures

Last year, Christopher Nolan’s Interstellar presented perhaps the most realistic representation of time travel yet from a scientific perspective. Using real concepts of gravitational time dilation the film saw its characters experiencing time at different rates depending on their relative position to a black hole – a scenario that would actually happen if we found ourselves too close to one. But then, can such concepts be described as time travel at all if they’re rooted in real science?

The genre – and with 6 mainstream American films using time travel in 2014, it is time for it to be considered a genre – has proven over a century to consistently provide ideas and narratives that capture audiences, and can translate itself to action, drama and comedy with equal success. There is clearly something encased in the simple idea of a protagonist travelling to another point in time that captures the attention and imagination of cinema audiences, and there is endless potential for more. If only we could travel to the future and see where it’s at in 30 years time.

What is your favourite use of time travel in film? Let us know in the comments!

(top image: Back To The Future – source: Universal Pictures)

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Sam is an English Literature student at the University of Sheffield. He likes film, writing, and writing about film. He didn't think Prometheus was that bad.

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10 Reasons Why Aruba Is The Perfect Destination For First Time International Travelers

Aruba offers direct flights from major US cities, making it an easy and stress-free destination for first-time international travelers.
English is widely spoken in Aruba, making it easy for North American travelers to communicate and navigate the island.
Aruba has a convenient online transit application process and visa-free entry, making it hassle-free for travelers.

According to the U.S. Department of State, Aruba welcomes over 2 million travelers every year, and 80% of that figure is made up of tourists from the United States. It's no wonder, with Aruba's stunning beaches and no shortage of things to discover in its capital of Oranjestad , the country is a slice of heaven in the form of a tropical paradise. Aruba also boasts many repeat visitors, according to locals, especially North American travelers.

So, what makes Aruba so appealing to Americans and other North American travelers? What is it about the island that makes people want to come back? And more importantly, why should travelers choose Aruba in the first place, especially for those who've never traveled internationally before? Read on to find out why Aruba is a first-time international traveler's ideal destination!

Related: These Are The 10 Cheapest Winter Destinations For Snowbirds in Aruba

Direct Flights From The US

From over a dozen american cities with trusted domestic carriers.

As evidenced by this popular query on TripAdvisor , dealing with connections, figuring out how checked bags factor in, and navigating unfamiliar airports may be extremely stressful, especially for first-time flyers and/or international travelers. Instead, travelers have plenty of choice to fly directly to Oranjestad from the central and eastern parts of the United States.

As frequent international travelers can attest, if flying a connection back to the US from abroad, the first city of arrival back in the U.S. requires travelers to recheck baggage after clearing immigration and customs as well as go through security a second time with TSA. Those unfamiliar with the process can find it very stressful and not-so-clear, not to mention tight connections run the risk of being missed. Don't ruin the memories of a perfectly good vacation with this process. Instead, Aruba allows for a truly international-feeling holiday, with direct, rather short, flights for easy travel.

Carriers That Fly Direct: Jetblue, American, United, Southwest, Spirit, and Delta
Major North American Cities Serviced: Toronto, Chicago, Boston, Dallas, Orlando, New York, Baltimore, Houston, Charlotte, Miami, Newark, Atlanta, Philadelphia, Fort Lauderdale, Washington D.C., and Minneapolis

English--And Many Other Languages--Are Widely Spoken In Aruba

Other widely spoken languages: dutch, spanish, french, chinese, italian.

With over 80 ethnic identities and nationalities represented among the residents of the island, the Aruba Convention Bureau explains that this melting pot of cultures and diverse peoples living happily among one another earns the island the moniker "One Happy Island." English has become a dominant language on the island, so international travelers from the US and North America won't have any issues navigating around Aruba. Nothing is lost in translation for North American travelers-- most residents speak multiple languages, including English, Spanish, Dutch, German, and the local dialect of Papiamiento. Further, this is the perfect place for visitors to dip their toes into the larger Caribbean area's rich history of immigration and complex colonial legacy, given its language accessibility.

Number of Residents: 106,537
Official Language: Dutch and Papiamiento
Languages Widely Spoken: English, Dutch, Spanish, French, Chinese, Italian

Easy Online Transit Applications And Visa-Free!

The travel authorization form is automated.

Though the USA and Canada's passports are some of the strongest in the world, many countries require Visas for travelers to transit there. NerdWallet recommends checking Visa requirements as the number 1 thing first-time travelers need to do ahead of their travels. However, Aruba's travel authorization form called the Embarkation and Disembarkation Card ("ED Card"), is easily accessible online for quick completion and approval.

All travelers to Aruba, including residents, need to fill this form out, and it's not considered a Visa in any way. Approval, in the form of a printable card or an email, does not take long--in fact, approvals can come in minutes, so it's simple for travelers to check things off their list and get it done. Simply present the ED Card with your passport at immigration upon landing in Aruba, and then you can start your holiday under the Caribbean sun!

Information Needed: Vital Information (Name, DOB), Passport Information, Travel Plans, Minor Health Information
Timeline: Application takes approximately 20 minutes to complete; apply up to 7 days before arrival
Cost Of ED Card: Free!

Related: The Complete Guide To Traveling Solo For The First Time

Visitors Can Stay With Familiar And Trusted Hotel Brands

Like the aruba marriott.

When traveling abroad, having a community around oneself can help relieve any travel stress or anxiety about how to navigate the island, where to get a meal, or what activities to choose. Nervous first-time travelers will be relieved to receive high levels of service coupled with ease and comfort when staying with familiar and trusted hotel brands like the Aruba Marriott Stellaris Casino . We had the pleasure of staying with the Aruba Marriott and can positively say being with a familiar brand with a fantastic selection of food, a stunning beach, and multiple pools made our stay on Aruba all that much better.

Sample Room Cost at the Aruba Marriott Stellaris Casino: High Season (January) Rate- $899 per night for a base King Room; Low Season (June) Rate- $500 per night for a base King Room
Best Amenities at the Aruba Marriott : 8 onsite eateries (including familiar brands like Starbucks and Ruth's Chris Steakhouse), both adult-only and family pools, direct beach access with rentable palapas, and complimentary onsite parking

While booking all-inclusive can be extremely convenient, Aruba offers more half-board or traditional hotel accommodations than all-inclusive ones. Given the island's friendly atmosphere, English-language use, and relatively easy navigability, Aruba is a perfect destination to skip an all-inclusive resort and explore the local food, adventure, and tour scene individually, especially for those traveling outside the United States/North America for the first time. Sites like the Aruba Convention Bureau's Aruba.com provide lists of trusted tour operators for those hoping to explore. Though, if you'd prefer an all-inclusive, Aruba's best are listed here .

Small Details Like Electric Outlets And Voltage Are the Same In Aruba As The US

No need to mess around with adapters or converters to power electronic devices.

Have you ever heard of those horror stories of blow dryers accidentally sparking fires or phone chargers causing major blackouts (think of Leap Year 's Amy Adams trying to charge her Blackberry!)? That's because the U.S.'s electric plugs and outlets are commonly Type A or Type B outlets (two flat prongs, sometimes with a round center prong between them) and 120 volts of electricity.

Many other places in the world, however, including Europe and the United Kingdom, actually use Types C-F and Type G, respectively (mostly round pins), and measure at 220-240 volts. Given the incompatibilities in both style and voltage, sometimes American appliances like curling irons are unusable abroad. Sounds complicated, right? Well, in Aruba, first-time travelers have nothing to worry about since it's exactly the same as the U.S. to Aruba!

Common Appliances Affected By Voltage Differences: Hair appliances (dryers, straighteners, curling irons), facial shavers, some steamers/irons, and some small plug-in fans

Customs Pre-Clearance At Aruba Airport

One of only six countries where clearing customs on flights going to the us is possible.

Major airports like Toronto Pearson International Airport in Canada and Dublin International Airport in Ireland offer pre-clearance services for travelers headed to the United States, and Aruba does, too! While it may seem like a longer process and a bit of hassle on the departure end, given one has to go through Customs and Border Patrol at the departure airport, it actually saves travelers time upon arrival in the United States. No long lines at passport control or having to wait for customs to inquire about baggage at the US destination airport--just an easy arrival process as if flying on a domestic flight!

Recommended Arrival Time for Departures from Aruba Airport: 2 hours before during non-peak season (summer), 2-3 hours before during peak season (winter); no more than 3 hours early since check-in won't be open until then
Other Major Airports with Pre-Clearance: Toronto Pearson, Dublin, Shannon, Nassau (Bahamas), Vancouver, and Calgary. A full list can be found on the Customs and Border Patrol website here .

Amazing Local Cuisine Familiar To Americans

A melting pot of cultures, flavors, and cuisines.

With so many nationalities represented on the island and with high visitation from North American travelers, it's not uncommon to see local delicacies listed alongside international favorites on one menu. It's completely understandable for first-time travelers out of the country to be a little homesick for recognizable food during a vacation. Aruba is a great place for a bit of cuisine exploration while also having the readily available option of getting some comfort food on the plate when needed.

Best Local Dishes: Pastechi (fried pastry pockets like a small calzone with different fillings), Keshi Yena (Aruban cheese casserole), and Siboyo Tempera (marinated onions and Madame Jeanette peppers)
Best Globally Recognizable Dishes: Grilled Caribbean Rock Lobster, Steamed Shrimp, and Catch-of-the-Day Fish with Aruban spices and hot sauce
Must-Try Local Restaurants: The West Deck Island Grill and Beach Bar and Atardi Restaurant at the Aruba Marriott

Related: Aruba Has More To Offer Than Just Beaches And All-Inclusive Resorts

No Joke, The Best Tap Water Around

Aruba obtains most of its fresh water from desalination plants.

Aruba boasts that it has some of the highest-quality tap water in the world, so much so that they are partnering with world-famous water sommeliers (yes, that's really a thing) to create travel experiences tasting all that Aruban water has to offer. Eager water travelers can even tour the major desalination plant on the island to learn more about the process that achieves this tasty and, most importantly, safe drinking water. While travelers going abroad for the first time may not be up for a plant tour, they can rest assured that the water that they're drinking and using in the restrooms and showers is clean and safe.

Best Water Tourism Opportunity (For the Curious Traveler!): W.E.B Desalination Plant Tour to see where the water magic happens!
Best (On-Water) Tour : De Pam Tours Snorkel Cruise to snorkel among shipwrecks and vivid sea life

Just a gentle reminder that the "ABC Islands" (Aruba, Bonaire, and Curacao) are very close to the equator. According to the US Environmental Protection Agency , the sun's UV rays are stronger in that geographic region due to the sun's constant proximity and straight overhead position. Remember to drink water consistently, even more so than at home, to avoid heat spells and dehydration. Take advantage of the tasty tap water with refillable water bottles to carry with you, and of course, use sunscreen! Aruba has some of the best aloe-based, water-resistant sunscreens on the market, like this one here .

A Balance Of Cultural And Adventure Activities

Aruba has a rich history, but for those seeking more thrills, the island has the best of both.

Traveling abroad offers some great opportunities to learn about the destination and the world at large--history, culture, and customs are all interesting things to learn about while traveling. However, sometimes visitors are looking for an experience that's less cerebral and a bit more visceral. Aruba has a great selection of both kinds of activities, an equal balance of learning about the island and its history and experiencing all the activities that the island has to offer. Aruba is also particularly well suited for solo travelers looking for a similar blend of experience themes.

Best Cultural Tour: Aruba Bus Sightseeing Tours with De Palm Tours
Best Activity-Based Tours: UTV Riding with De Palm Tours , Bicycling with Aruba Active Vacations ; For a full list of the best tours of Aruba , read here!

Both American Dollars And Aruban Florins Are Readily Accepted

First-time international travelers don't have to worry about currency exchanges ahead of travel.

Named one of the top 10 things a traveler must take care of before traveling abroad by NerdWallet , arranging for currency conversions ahead of travel or having to make that extra stop at the airport is just an extra layer of worry for people traveling abroad. Avoid having to undertake the hassle by traveling to a USD-friendly destination like Aruba. Aruban businesses readily accept American dollars, and many bank ATMs also dispense in American dollars. No need to worry about conversion rates while shopping or dining out-- everything will be as if one were purchasing things at home!

Best Shopping Spots To Spend Those American Dollars: " The Local Market " (across from the cruise ship terminal), Renaissance Marketplace , and Duty-Free Stores ; for a full list of local artisans, read here !

10 Reasons Why Aruba Is The Perfect Destination For First Time International Travelers

Screen Rant

Dc’s first flash finally calls out barry allen for his flashpoint disaster.

As the first Flash, Jay Garrick has inspired generations of heroes — but the Crimson Comet has one more time travel lesson to teach his successors.

Warning: Contains SPOILERS for Jay Garrick: The Flash #6

Jay Garrick reveals he doesn't believe speedsters should use time travel in Jay Garrick: The Flash #6.
Past time travel mistakes, like in Flashpoint, still have consequences in the present-day of the DC Universe.
Jay Garrick will always be the North Star of the Flash Family, even after spending years in the Speed Force thanks to Barry's time travel mistake.

The Flash is a legacy that has been passed down through generations of heroes, but the original Crimson Comet – Jay Garrick – still holds a special place in DC’s pantheon of heroes. A surrogate grandfather to the Flash Family and to the hero community at large, when Jay speaks, his allies listen. And now, Jay has subtly spoken out against his successor Barry Allen’s greatest mistake – Flashpoint.

Jay Garrick: The Flash #6 by Jeremy Adams and Diego Olortegui sees the titular speedster racing against the clock to foil Doctor Elemental. Pushing himself to the limit to save his daughter, Jay knows he’s slower than his successors, saying that he can’t time-travel — before claiming that no speedster was ever meant to.

Concentrating, Garrick says, “ We’re made to look forward. Good or bad. To face joy and defeat head-on. ” And considering how Flashpoint spawned from Barry’s messing with the timestream, it’s hard not to read this as a partial rebuke of the second Flash’s greatest blunder .

Flashpoint by Geoff Johns, Andy Kubert, Sandra Hope, Alex Sinclair, and Nick J. Napolitano is available now digitally and in collected editions from DC Comics.

Flash Introduces the Grossest Anti-Speedster Contingency in DC History (Arachnophobes Beware)

Jay garrick knows time travel is always a mistake, the flashes are still recovering from flashpoint.

Barry Allen is one of DC's iconic heroes, but the scars left by Flashpoint are still prominent in the DC Universe as a whole. The Flashes in particular have spent a long while recovering from the timestream’s alterations, only fully reuniting the Flash Family in recent years after the majority of speedsters – like Jay, Impulse, and Wally West – were trapped in the Speed Force for years . Having spent years out of time, it’s no wonder that Jay would still be a little bitter, but odds are his words are meant to be more inspirational than admonishing.

The Flash Family are an iconic piece of DC Comics lore, and more so than many other corners of the DC Universe, these heroes play fundamental roles within the cosmic tapestry of their multiverse.

As the first Flash, Jay Garrick has always been a signpost of DC’s hero community, racing towards the future with a wink and a charm that can’t help but inspire his successors. This Flash truly believes that it’s the responsibility of heroes to move forward , guiding the way for those they inspire, and his legacy within the Flash Family lends that belief a lot of credibility. To Jay, the legacy of the Flash is about facing tomorrow with hope, not getting tangled up in the past – a fact all too forgotten by many of the younger speedsters out there.

The Flash Legacy Will Always Move Forward

Nobody inspires other speedsters quite like jay garrick.

The Flash Family are an iconic piece of DC Comics lore , and more so than many other corners of the DC Universe, these heroes play fundamental roles within the cosmic tapestry of their multiverse. Whether it’s a crisis in time or the multiverse, a Flash will be there to help save the day by looking forward , not backward. And with the original Flash back to his place of prominence among the Fastest Family Alive, Jay Garrick will be there to keep his successors moving forward.

Jay Garrick: The Flash #6 is available now from DC Comics.

The Flash is the superhero name given to the D.C. comics character who utilizes unparalleled speed tied to a dimensional power known as the "speed force" o overwhelm their opposition. Premiering in 1939, the original Flash arrived as Jay Garrick. Still, it would be superseded by Barry Allen in popularity and featured status, but the Flash is one character that has met many of their alternate selves. The character is typically seen as a part of the Justice League in nearly all incarnations.

protestors in New York on the first earth day in 1970

HISTORY & CULTURE

This is the story of the first Earth Day—and why it mattered

The April 22 holiday arose from public outrage over a California oil spill. It also helped pave the way for key environmental protections.

Each year on April 22, people around the globe come together to honor and conserve their shared home: Earth.

Known as Earth Day, the holiday got its start in the United States in 1970 as a teach-in on college campuses. It has since evolved into a global celebration of the environmental movement’s achievements—and a reminder of the work yet to be done.

( 5 simple things you can do to live more sustainably .)

The same wave of activism that led to the creation of Earth Day also ushered in a new age of environmental legislation—one that saw the passage of the Clean Air Act and Clean Water Act as well as the creation of the Environmental Protection Agency. Here’s how Earth Day came to be a holiday—and why activists hope it will continue to shape a more sustainable future.

When was the first Earth Day?

The 1960s was a decade of environmental awakening for much of the United States. Most Americans were introduced to the effects of air pollution in 1962 when naturalist and former marine biologist Rachel Carson published Silent Spring . In the influential book, Carson meticulously chronicled how DDT, a then-widespread pesticide, entered the food chain and caused cancer and genetic damage in humans and animals.

Silent Spring was an instant bestseller, causing people to question modern technology’s impact on the environment, while setting the stage for the environmental movement to accelerate.

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( What you need to know about pesticides and other toxic waste .)

One of the original titans of the environmental movement was the father of Earth Day, former Democratic Senator Gaylord Nelson from Wisconsin. A staunch progressive and wilderness lover, Nelson made it his priority to pass environmental legislation like the 1964 Wilderness Act, which safeguarded federal land, and the 1968 Wild and Scenic Rivers Act, which established a process for protecting free-flowing rivers.

Then, in January 1969, a devastating oil spill in Santa Barbara, California, inspired Nelson to spearhead a new grassroots approach to the environmental movement. The oil spill , which killed thousands of birds and stained beaches along the California coast, was the largest the U.S. had seen at the time and remains the worst in California’s history.

a black and white photograph of an duck covered in oil on a beach

Stirred by the energy of students participating in anti-war protests, Nelson set out to galvanize the same kind of action on behalf of the environment. He pitched an idea for a teach-in—dedicated discussions between faculty and students about the environment. He selected April 22, 1970, a date between Spring Break and final exams, to allow for maximum student participation.

Nelson recruited Pete McCloskey, a California Republican representative, and Denis Hayes, a young activist, to help organize the sit-in. Soon, the effort ballooned into what is now dubbed the Earth Day protest. By April 22, interest had grown so much that 20 million Americans at 2,000 colleges and universities and 10,000 grade schools participated in the first Earth Day through demonstrations, decluttering rivers, and more.

Polls from the time showed that concern for the environment had leapt to the forefront of public opinion—with air and water pollution even perceived as more important than issues of race and crime. In a 1971 poll, 78 percent of Americans indicated they would be willing to pay to clean up their air and water.

“The reason Earth Day worked is that it organized itself,” Nelson told the New York Times . “The idea was out there and everybody grabbed it. I wanted a demonstration by so many people that politicians would say, ‘Holy cow, people care about this.’”

Why is Earth Day so important?

While Nelson led the charge, the groundswell of public support for environmental legislation had generated widespread support in Congress and the White House. The momentum of the first Earth Day protest carried throughout the year—and amounted to some of the strongest environmental legislation to date.

By the end of 1970, President Richard Nixon signed into law the National Environmental Policy Act, the Occupational Safety and Health Act, and the Clean Air Act, which respectively lay the groundwork for government agencies to assess the environmental impact of their actions, set health and safety standards in workplaces, and allowed regulation of air emissions.

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( The Clean Air Act saved millions of lives and trillions of dollars .)

To more effectively oversee and centralize any environmental regulations, Nixon created the United States Environmental Protection Agency—which was established just eight months after the first Earth Day.

Concern for protecting the environment continued throughout the 1970s as Congress passed the Clean Water Act, regulating pollutant discharges in U.S. waters, the Endangered Species Act protecting wildlife from extinction, and the Federal Insecticide, Fungicide, and Rodenticide Act, which regulated pesticides.

Nelson was at the center of most of these major environmental bills, specifically the Clean Air and Water Acts and the Endangered Species Act. He expanded his environmental activism and became a principal sponsor for laws that preserved the Appalachian Trail, established fuel efficiency standards, and banned DDT.

Just 10 years after the first Earth Day, Nelson wrote in the EPA Journal that predictions of the end of the golden era of environmentalism were preemptive and inaccurate.

( Forget your carbon footprint—your climate shadow is what really matters .)

“To anyone who has paid attention, it is clear that the environmental movement now is far stronger, far better led, far better informed, and far more influential than it was ten years ago. Its strength grows each year because public knowledge and understanding grow each year,” Nelson wrote.

The Earth Day movement went global for its 20th anniversary: Hayes organized a campaign that mobilized 200 million people to boost environmental issues and promote recycling through rallies and a drum chain in Gabon. This paved the way for a 1992 United Nations conference in Brazil focused on the environment, dubbed the “ Earth Summit ,” signaling a more serious effort from global governing bodies towards sustainability.

A few years later, Nelson’s contributions to the environment were honored in the form of a Presidential Medal of Freedom in 1995. Nelson continued to spearhead environmental activism in the new millennium, but this time he focused on the latest priorities: global warming and clean energy.

How is Earth Day celebrated?

Since its original conception as a teach-in, Earth Day has become a global phenomenon paving the way not only for protests and legislation, but also for volunteering and habitat clean-ups. The holiday now largely focuses on combating climate change. Its official site —which is managed by Environmental Action, Inc., the modern incarnation of the group that organized the first Earth Day—cites “climate change deniers” and “oil lobbyists” as two of the biggest hurdles for the modern movement.

Climate change continues to stir debate as Earth experiences a rise in the frequency of wildfires, extreme storms, and harsh weather, which also has increased the number of displaced communities. The UN’s Intergovernmental Panel on Climate Change published a report in 2022 urging immediate action to slow the effects of climate change, warning of severe health consequences and worsening social inequities

( Meet the young activists demanding climate action .)

While scientists nurture nature to help slow the effects of climate change, activists continue to raise the alarm. Young people in particular are leading the charge both on college campuses and in the international sphere through prominent voices like Greta Thunberg.

“I don’t want your hope, I don’t want you to be hopeful,” Thunberg famously said at the 2019 World Economic Forum in Davos, Switzerland . “I want you to panic and act as if the house was on fire.”

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Who was last Michigan QB drafted in NFL draft's first round? J.J. McCarthy set to make history

After helping lead Michigan football to a 15-0 record, its third-consecutive Big Ten championship and the program’s first national championship since 1997, J.J. McCarthy has more accomplishments in front of him.

If projections are to be believed, McCarthy will be a first-round pick on Thursday night in the 2024 NFL Draft in Detroit. Many outlets pegging him as a top-10 selection.

It will put him in a rare position among Wolverines quarterbacks.

REQUIRED READING: ESPN's Dan Orlovsky: J.J. McCarthy will be 'early favorite' for NFL OROY with Vikings

Though Michigan is the winningest program in college football history and is one of the schools synonymous with the sport, it doesn’t have a lengthy list of former quarterbacks who have been drafted into the NFL and excelled in the professional ranks once there — though, of course, there’s a certain sixth-round pick from the 2000 NFL Draft who more than makes up for that relative dearth.

NFL DRAFT HUB: Latest NFL Draft mock drafts, news, live picks, grades and analysis.

As McCarthy is poised to make program history Thursday night, here’s a look at the history of Michigan quarterbacks in the NFL draft:

When was the last time a Michigan quarterback was drafted in first round?

While it’s possible McCarthy won’t be selected as high as some mock drafts have him, it’s a virtual certainty that, as the widely accepted No. 4 quarterback in the class, he will be taken in the first round of the 2024 NFL Draft on Thursday.

Should he manage to do that, he’ll be just the second Michigan quarterback ever selected in the first round, according to Pro Football Reference’s database. The only other quarterback to earn that distinction is none other than McCarthy’s coach with the Wolverines.

Jim Harbaugh was the No. 26 overall pick in the 1987 NFL Draft, landing with the Chicago Bears, with whom he spent the first seven seasons of his career.

REQUIRED READING: Where will Blake Corum be drafted? Chargers, Colts lead list of 2024 NFL Draft landing spots

Highest-picked Michigan quarterback in NFL draft history

Entering the 2024 NFL Draft, Harbaugh is the highest-drafted Michigan quarterback in the history of the draft. He went No. 26 overall, making it a virtual certainty that McCarthy will be the highest-drafted QB in Wolverines history by the conclusion of Thursday's first round.

Michigan quarterback selected in NFL draft

According to Pro Football Reference’s database, 14 Michigan players who classified as quarterbacks have been selected in the NFL draft over the event’s nearly 90-year history, with McCarthy set to make it 15.

Here is a list of the former Wolverines quarterbacks selected in the NFL draft, in order of draft position:

Jim Harbaugh, 1987 : Chicago Bears, first round, No. 26 overall pick
Steve Smith, 1984* : San Diego Chargers, second round, No. 33 overall pick
Todd Collins, 1995 : Buffalo Bills, second round, No. 45 overall pick
Jim Van Pelt, 1958 : Washington, fifth round, No. 54 overall pick
Chad Henne, 2008 : Miami Dolphins, second round, No. 57 overall pick
Bob Ptacek, 1959 : Cleveland Browns, eighth round, No. 87 overall pick
Brian Griese, 1998 : Denver Broncos, third round, No. 91 overall pick
Rick Leach, 1979 : Broncos, fifth round, No. 132 overall pick
Jake Rudock, 2016 : Detroit Lions, sixth round, No. 191 overall pick
Drew Henson, 2003 : Houston Texans, sixth round, No. 192 overall pick
Tom Brady, 2000 : New England Patriots, sixth round, No. 199 overall pick
John Navarre, 2004 : Arizona Cardinals, seventh round, No. 202 overall pick
Elvis Grbac, 1993 : San Francisco 49ers, eighth round, No. 219 overall pick
Larry Cipa, 1974 : New Orleans Saints, 15 th round, No. 373 overall pick

* Supplemental draft

REQUIRED READING: Where will Roman Wilson be drafted? Bengals, Steelers lead list of 2024 NFL Draft landing spots

Where will Michigan’s J.J. McCarthy go in 2024 NFL Draft?

Here’s a look at where various mock drafts have McCarthy pegged to go:

USA TODAY : New England Patriots, first round, No. 3 overall pick
ESPN’s Mel Kiper : Minnesota Vikings (via trade with Los Angeles Chargers), first round, No. 5 overall pick
ESPN’s Field Yates : Vikings (via trade with Chargers), first round, No. 5 overall pick
CBS Sports : Vikings (via trade with Chargers), first round, No. 5 overall pick
The Athletic : Vikings (via trade with Cardinals), first round, No. 4 overall pick
NFL Network : New York Giants (via trade with Cardinals), first round, No. 4 overall pick
Pro Football Focus : Vikings (via trade with Chargers), first round, No. 5 overall pick

Today in Sports – 4 QBs are taken in the top 10 selections for first time in NFL Draft history

The Associated Press

April 25, 2024, 10:10 AM

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1905 — Jack McCarthy of the Cubs became the only outfielder in major league history to throw out three runners at the plate, each of whom became the second out of a double play. The victims were the Pittsburgh Pirates in a 2-1 loss.

1912 — 1st homerun hit at Fenway Park (Hugh Bradley, Red Sox).

1931 — Lou Gehrig hits a HR but is called out for passing a runner, mistake costs him AL home run crown; he & Babe Ruth tie for season.

1950 — The University of Miami ends the longest winning streak in collegiate tennis by defeating William & Mary 8-1. William & Mary, unbeaten in five years, had won 82 consecutive meets.

1952 — Patty Berg scores 64, best competitive round of golf by a woman.

1961 — Roger Maris hits 1st of 61 homers in 1961.

1964 — The Boston Celtics capture their sixth consecutive NBA title with a 105-99 victory over the San Francisco Warriors in Game 5 of the finals.

1966 — Red Auerbach retires as Boston Celtic’s coach.

1983 — NFL Draft: Stanford quarterback John Elway first pick by Baltimore Colts.

1992 — NFL Draft: University of Washington defensive end Steve Emtman from first pick by Indianapolis Colts.

1995 — The Colorado Rockies post an 11-9 victory over the New York Mets in 14 innings, tying the NL record for innings played in a season opener.

2002 — Odalis Perez of Los Angeles faces the minimum 27 batters in his first career shutout. Perez was perfect for six innings in a 10-0 win over the Cubs at Chicago’s Wrigley Field.

2003 — NFL Draft: USC quarterback Carson Palmer first pick by Cincinnati Bengals.

2008 — NFL Draft: University of Michigan offensive tackle Jake Long first pick by Miami Dolphins.

2009 — French swimmer Frederick Bousquet sets a world record in the 50-meter freestyle, becoming the first person to break the 21-second barrier. Bousquet breaks the record at the French championships finishing in 20.94 seconds.

2012 — Stanford quarterback Andrew Luck is selected first overall in the NFL draft by the Indianapolis Colts, followed by Baylor QB Robert Griffin III, who is taken by the Washington Redskins.

2012 — The Charlotte Bobcats finish with the worst winning percentage in NBA history after a 104-84 loss to the New York Knicks. The Bobcats’ 23rd consecutive loss leaves them with a winning percentage of .106 (7-59) in the lockout-shortened season. The record was set 39 years ago, when the 1972-73 Philadelphia 76ers finished 9-73 (.110) in a full regular season.

2014 — Wladimir Klitschko toys with Alex Leapai and knocks him out in the fifth round to retain his four heavyweight belts in Oberhausen, Germany.

2015 — FC Bayern Munich wins the 2014–15 Bundesliga for a 25th time.

2018 — Oklahoma quarterback Baker Mayfield first pick by Cleveland Browns; 4 QBs taken in top 10 selections for first time in history.

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10 Reasons Why Aruba Is The Perfect Destination For First Time International Travelers

Direct Flights From The US

English--And Many Other Languages--Are Widely Spoken In Aruba

Easy Online Transit Applications And Visa-Free!

Visitors Can Stay With Familiar And Trusted Hotel Brands

Small Details Like Electric Outlets And Voltage Are the Same In Aruba As The US